Merge remote-tracking branch 'origin/master' into capablerobot-usbhub

37 files changed, 547 insertions, 163 deletions

diff --git a/py/binary.c b/py/binary.c
index 6b46425cf..2ec12fa93 100644
--- a/py/binary.c
+++ b/py/binary.c
@@ -184,7 +184,7 @@ long long mp_binary_get_int(mp_uint_t size, bool is_signed, bool big_endian, con
         val = -1;
     }
     for (uint i = 0; i < size; i++) {
-        val <<= 8;
+        val *= 256;
         val |= *src;
         src += delta;
     }
diff --git a/py/circuitpy_defns.mk b/py/circuitpy_defns.mk
index a6dde61da..1f2d6c73e 100644
--- a/py/circuitpy_defns.mk
+++ b/py/circuitpy_defns.mk
@@ -114,11 +114,21 @@ endif
 ifeq ($(CIRCUITPY_AUDIOCORE),1)
 SRC_PATTERNS += audiocore/%
 endif
+ifeq ($(CIRCUITPY_AUDIOMIXER),1)
+SRC_PATTERNS += audiomixer/%
+endif
+ifeq ($(CIRCUITPY_AUDIOMP3),1)
+SRC_PATTERNS += audiomp3/%
+endif
 ifeq ($(CIRCUITPY_BITBANGIO),1)
 SRC_PATTERNS += bitbangio/%
 endif
+# Some builds need bitbang SPI for the dotstar but don't make bitbangio available so include it separately.
+ifeq ($(CIRCUITPY_BITBANG_APA102),1)
+SRC_PATTERNS += bitbangio/SPI%
+endif
 ifeq ($(CIRCUITPY_BLEIO),1)
-SRC_PATTERNS += bleio/%
+SRC_PATTERNS += _bleio/%
 endif
 ifeq ($(CIRCUITPY_BOARD),1)
 SRC_PATTERNS += board/%
@@ -217,9 +227,18 @@ ifeq ($(CIRCUITPY_PEW),1)
 SRC_PATTERNS += _pew/%
 endif
 
-# All possible sources are listed here, and are filtered by SRC_PATTERNS.
-SRC_COMMON_HAL = \
-$(filter $(SRC_PATTERNS), \
+# All possible sources are listed here, and are filtered by SRC_PATTERNS in SRC_COMMON_HAL
+SRC_COMMON_HAL_ALL = \
+	_bleio/__init__.c \
+	_bleio/Adapter.c \
+	_bleio/Attribute.c \
+	_bleio/Characteristic.c \
+	_bleio/CharacteristicBuffer.c \
+	_bleio/Connection.c \
+	_bleio/Descriptor.c \
+	_bleio/PacketBuffer.c \
+	_bleio/Service.c \
+	_bleio/UUID.c \
 	analogio/AnalogIn.c \
 	analogio/AnalogOut.c \
 	analogio/__init__.c \
@@ -230,16 +249,6 @@ $(filter $(SRC_PATTERNS), \
 	audiopwmio/PWMAudioOut.c \
 	audioio/__init__.c \
 	audioio/AudioOut.c \
-	bleio/__init__.c \
-	bleio/Adapter.c \
-	bleio/Central.c \
-	bleio/Characteristic.c \
-	bleio/CharacteristicBuffer.c \
-	bleio/Descriptor.c \
-	bleio/Peripheral.c \
-	bleio/Scanner.c \
-	bleio/Service.c \
-	bleio/UUID.c \
 	board/__init__.c \
 	busio/I2C.c \
 	busio/SPI.c \
@@ -271,38 +280,35 @@ $(filter $(SRC_PATTERNS), \
 	rtc/__init__.c \
 	supervisor/Runtime.c \
 	supervisor/__init__.c \
-	time/__init__.c \
-	touchio/TouchIn.c \
-	touchio/__init__.c \
-)
+	time/__init__.c
+
+SRC_COMMON_HAL = $(filter $(SRC_PATTERNS), $(SRC_COMMON_HAL_ALL))
 
 # These don't have corresponding files in each port but are still located in
 # shared-bindings to make it clear what the contents of the modules are.
 # All possible sources are listed here, and are filtered by SRC_PATTERNS.
 SRC_BINDINGS_ENUMS = \
 $(filter $(SRC_PATTERNS), \
+	_bleio/Address.c \
+	_bleio/Attribute.c \
+	_bleio/ScanEntry.c \
 	digitalio/Direction.c \
 	digitalio/DriveMode.c \
 	digitalio/Pull.c \
 	fontio/Glyph.c \
 	microcontroller/RunMode.c \
 	math/__init__.c \
-	supervisor/__init__.c \
 )
 
 SRC_BINDINGS_ENUMS += \
 	help.c \
 	util.c
 
-SRC_BINDINGS_ENUMS += \
-$(filter $(SRC_PATTERNS), \
-	bleio/Address.c \
-	bleio/ScanEntry.c \
-)
-
-# All possible sources are listed here, and are filtered by SRC_PATTERNS.
-SRC_SHARED_MODULE = \
-$(filter $(SRC_PATTERNS), \
+SRC_SHARED_MODULE_ALL = \
+	_bleio/Address.c \
+	_bleio/Attribute.c \
+	_bleio/ScanEntry.c \
+	_bleio/ScanResults.c \
 	_pixelbuf/PixelBuf.c \
 	_pixelbuf/__init__.c \
 	_stage/Layer.c \
@@ -311,20 +317,23 @@ $(filter $(SRC_PATTERNS), \
 	audiopwmio/__init__.c \
 	audioio/__init__.c \
 	audiocore/__init__.c \
-	audiocore/Mixer.c \
 	audiocore/RawSample.c \
 	audiocore/WaveFile.c \
+	audiomixer/__init__.c \
+	audiomixer/Mixer.c \
+	audiomixer/MixerVoice.c \
+	audiomp3/__init__.c \
+	audiomp3/MP3Decoder.c \
 	bitbangio/I2C.c \
 	bitbangio/OneWire.c \
 	bitbangio/SPI.c \
 	bitbangio/__init__.c \
 	board/__init__.c \
-	bleio/Address.c \
-	bleio/ScanEntry.c \
 	busio/OneWire.c \
 	displayio/Bitmap.c \
 	displayio/ColorConverter.c \
 	displayio/Display.c \
+	displayio/EPaperDisplay.c \
 	displayio/FourWire.c \
 	displayio/Group.c \
 	displayio/I2CDisplay.c \
@@ -350,7 +359,48 @@ $(filter $(SRC_PATTERNS), \
 	uheap/__init__.c \
 	ustack/__init__.c \
 	_pew/__init__.c \
-	_pew/PewPew.c \
+	_pew/PewPew.c
+
+# All possible sources are listed here, and are filtered by SRC_PATTERNS.
+SRC_SHARED_MODULE = $(filter $(SRC_PATTERNS), $(SRC_SHARED_MODULE_ALL))
+
+# Use the native touchio if requested. This flag is set conditionally in, say, mpconfigport.h.
+# The presence of common-hal/touchio/* # does not imply it's available for all chips in a port,
+# so there is an explicit flag. For example, SAMD21 touchio is native, but SAMD51 is not.
+ifeq ($(CIRCUITPY_TOUCHIO_USE_NATIVE),1)
+SRC_COMMON_HAL_ALL += \
+	touchio/TouchIn.c \
+	touchio/__init__.c
+else
+SRC_SHARED_MODULE_ALL += \
+	touchio/TouchIn.c \
+	touchio/__init__.c
+endif
+ifeq ($(CIRCUITPY_AUDIOMP3),1)
+SRC_MOD += $(addprefix lib/mp3/src/, \
+	bitstream.c \
+	buffers.c \
+	dct32.c \
+	dequant.c \
+	dqchan.c \
+	huffman.c \
+	hufftabs.c \
+	imdct.c \
+	mp3dec.c \
+	mp3tabs.c \
+	polyphase.c \
+	scalfact.c \
+	stproc.c \
+	subband.c \
+	trigtabs.c \
+)
+$(BUILD)/lib/mp3/src/buffers.o: CFLAGS += -include "py/misc.h" -D'MPDEC_ALLOCATOR(x)=m_malloc(x,0)' -D'MPDEC_FREE(x)=m_free(x)'
+endif
+
+# All possible sources are listed here, and are filtered by SRC_PATTERNS.
+SRC_SHARED_MODULE_INTERNAL = \
+$(filter $(SRC_PATTERNS), \
+	displayio/display_core.c \
 )
 
 ifeq ($(INTERNAL_LIBM),1)
@@ -378,6 +428,18 @@ $(addprefix lib/,\
 	)
 endif
 
+ifdef LD_TEMPLATE_FILE
+# Generate a linker script (.ld file) from a template, for those builds that use it.
+GENERATED_LD_FILE = $(BUILD)/$(notdir $(patsubst %.template.ld,%.ld,$(LD_TEMPLATE_FILE)))
+#
+# ld_defines.pp is generated from ld_defines.c. See py/mkrules.mk.
+# Run gen_ld_files.py over ALL *.template.ld files, not just LD_TEMPLATE_FILE,
+# because it may include other template files.
+$(GENERATED_LD_FILE): $(BUILD)/ld_defines.pp boards/*.template.ld
+	$(STEPECHO) "GEN $@"
+	$(Q)$(PYTHON3) $(TOP)/tools/gen_ld_files.py --defines $< --out_dir $(BUILD) boards/*.template.ld
+endif
+
 .PHONY: check-release-needs-clean-build
 
 check-release-needs-clean-build:
diff --git a/py/circuitpy_mpconfig.h b/py/circuitpy_mpconfig.h
index d88d6538e..5b705a088 100644
--- a/py/circuitpy_mpconfig.h
+++ b/py/circuitpy_mpconfig.h
@@ -28,11 +28,12 @@
 // sure that the same feature set and settings are used, such as in atmel-samd
 // and nrf.
 
-#include <stdint.h>
-
 #ifndef __INCLUDED_MPCONFIG_CIRCUITPY_H
 #define __INCLUDED_MPCONFIG_CIRCUITPY_H
 
+#include <stdint.h>
+#include <stdatomic.h>
+
 // This is CircuitPython.
 #define CIRCUITPY 1
 
@@ -56,8 +57,8 @@
 #define MICROPY_COMP_MODULE_CONST        (1)
 #define MICROPY_COMP_TRIPLE_TUPLE_ASSIGN (0)
 #define MICROPY_DEBUG_PRINTERS           (0)
-#define MICROPY_EMIT_INLINE_THUMB        (0)
-#define MICROPY_EMIT_THUMB               (0)
+#define MICROPY_EMIT_INLINE_THUMB        (CIRCUITPY_ENABLE_MPY_NATIVE)
+#define MICROPY_EMIT_THUMB               (CIRCUITPY_ENABLE_MPY_NATIVE)
 #define MICROPY_EMIT_X64                 (0)
 #define MICROPY_ENABLE_DOC_STRING        (0)
 #define MICROPY_ENABLE_FINALISER         (1)
@@ -139,7 +140,6 @@
 #define MICROPY_VFS_FAT             (MICROPY_VFS)
 #define MICROPY_READER_VFS          (MICROPY_VFS)
 
-
 // type definitions for the specific machine
 
 #define BYTES_PER_WORD (4)
@@ -167,20 +167,25 @@ typedef long mp_off_t;
 #define mp_import_stat mp_vfs_import_stat
 #define mp_builtin_open_obj mp_vfs_open_obj
 
+
 // extra built in names to add to the global namespace
 #define MICROPY_PORT_BUILTINS \
     { MP_OBJ_NEW_QSTR(MP_QSTR_help), (mp_obj_t)&mp_builtin_help_obj }, \
     { MP_OBJ_NEW_QSTR(MP_QSTR_input), (mp_obj_t)&mp_builtin_input_obj }, \
     { MP_OBJ_NEW_QSTR(MP_QSTR_open), (mp_obj_t)&mp_builtin_open_obj },
 
-// board specific definitions
+//////////////////////////////////////////////////////////////////////////////////////////////////
+// board-specific definitions, which control and may override definitions below.
 #include "mpconfigboard.h"
 
 // CIRCUITPY_FULL_BUILD is defined in a *.mk file.
 
 // Remove some lesser-used functionality to make small builds fit.
 #define MICROPY_BUILTIN_METHOD_CHECK_SELF_ARG (CIRCUITPY_FULL_BUILD)
-#define MICROPY_CPYTHON_COMPAT                (CIRCUITPY_FULL_BUILD)
+//TODO: replace this with a rework of the FULL_BUILD system
+#if !defined(MICROPY_CPYTHON_COMPAT)
+	#define MICROPY_CPYTHON_COMPAT                (CIRCUITPY_FULL_BUILD)
+#endif
 #define MICROPY_MODULE_WEAK_LINKS             (CIRCUITPY_FULL_BUILD)
 #define MICROPY_PY_ALL_SPECIAL_METHODS        (CIRCUITPY_FULL_BUILD)
 #define MICROPY_PY_BUILTINS_COMPLEX           (CIRCUITPY_FULL_BUILD)
@@ -191,7 +196,9 @@ typedef long mp_off_t;
 #define MICROPY_PY_UERRNO                     (CIRCUITPY_FULL_BUILD)
 // Opposite setting is deliberate.
 #define MICROPY_PY_UERRNO_ERRORCODE           (!CIRCUITPY_FULL_BUILD)
+#ifndef MICROPY_PY_URE
 #define MICROPY_PY_URE                        (CIRCUITPY_FULL_BUILD)
+#endif
 #define MICROPY_PY_URE_MATCH_GROUPS           (CIRCUITPY_FULL_BUILD)
 #define MICROPY_PY_URE_MATCH_SPAN_START_END   (CIRCUITPY_FULL_BUILD)
 #define MICROPY_PY_URE_SUB                    (CIRCUITPY_FULL_BUILD)
@@ -212,6 +219,9 @@ typedef long mp_off_t;
 #define MP_SSIZE_MAX (0x7fffffff)
 #endif
 
+#if INTERNAL_FLASH_FILESYSTEM == 0 && QSPI_FLASH_FILESYSTEM == 0 && SPI_FLASH_FILESYSTEM == 0 && !CIRCUITPY_MINIMAL_BUILD
+#error No *_FLASH_FILESYSTEM set!
+#endif
 
 // These CIRCUITPY_xxx values should all be defined in the *.mk files as being on or off.
 // So if any are not defined in *.mk, they'll throw an error here.
@@ -244,6 +254,20 @@ extern const struct _mp_obj_module_t audioio_module;
 #define AUDIOIO_MODULE
 #endif
 
+#if CIRCUITPY_AUDIOMIXER
+#define AUDIOMIXER_MODULE         { MP_OBJ_NEW_QSTR(MP_QSTR_audiomixer), (mp_obj_t)&audiomixer_module },
+extern const struct _mp_obj_module_t audiomixer_module;
+#else
+#define AUDIOMIXER_MODULE
+#endif
+
+#if CIRCUITPY_AUDIOMP3
+#define AUDIOMP3_MODULE         { MP_OBJ_NEW_QSTR(MP_QSTR_audiomp3), (mp_obj_t)&audiomp3_module },
+extern const struct _mp_obj_module_t audiomp3_module;
+#else
+#define AUDIOMP3_MODULE
+#endif
+
 #if CIRCUITPY_AUDIOPWMIO
 #define AUDIOPWMIO_MODULE         { MP_OBJ_NEW_QSTR(MP_QSTR_audiopwmio), (mp_obj_t)&audiopwmio_module },
 extern const struct _mp_obj_module_t audiopwmio_module;
@@ -259,7 +283,7 @@ extern const struct _mp_obj_module_t bitbangio_module;
 #endif
 
 #if CIRCUITPY_BLEIO
-#define BLEIO_MODULE           { MP_OBJ_NEW_QSTR(MP_QSTR_bleio), (mp_obj_t)&bleio_module },
+#define BLEIO_MODULE           { MP_OBJ_NEW_QSTR(MP_QSTR__bleio), (mp_obj_t)&bleio_module },
 extern const struct _mp_obj_module_t bleio_module;
 #else
 #define BLEIO_MODULE
@@ -273,13 +297,7 @@ extern const struct _mp_obj_module_t board_module;
 #define BOARD_SPI (defined(DEFAULT_SPI_BUS_SCK) && defined(DEFAULT_SPI_BUS_MISO) && defined(DEFAULT_SPI_BUS_MOSI))
 #define BOARD_UART (defined(DEFAULT_UART_BUS_RX) && defined(DEFAULT_UART_BUS_TX))
 
-#if BOARD_I2C
-#define BOARD_I2C_ROOT_POINTER mp_obj_t shared_i2c_bus;
-#else
-#define BOARD_I2C_ROOT_POINTER
-#endif
-
-// SPI is always allocated off the heap.
+// I2C and SPI are always allocated off the heap.
 
 #if BOARD_UART
 #define BOARD_UART_ROOT_POINTER mp_obj_t shared_uart_bus;
@@ -289,7 +307,6 @@ extern const struct _mp_obj_module_t board_module;
 
 #else
 #define BOARD_MODULE
-#define BOARD_I2C_ROOT_POINTER
 #define BOARD_UART_ROOT_POINTER
 #endif
 
@@ -314,7 +331,9 @@ extern const struct _mp_obj_module_t terminalio_module;
 #define DISPLAYIO_MODULE       { MP_OBJ_NEW_QSTR(MP_QSTR_displayio), (mp_obj_t)&displayio_module },
 #define FONTIO_MODULE       { MP_OBJ_NEW_QSTR(MP_QSTR_fontio), (mp_obj_t)&fontio_module },
 #define TERMINALIO_MODULE      { MP_OBJ_NEW_QSTR(MP_QSTR_terminalio), (mp_obj_t)&terminalio_module },
-#define CIRCUITPY_DISPLAY_LIMIT (3)
+#ifndef CIRCUITPY_DISPLAY_LIMIT
+#define CIRCUITPY_DISPLAY_LIMIT (1)
+#endif
 #else
 #define DISPLAYIO_MODULE
 #define FONTIO_MODULE
@@ -580,6 +599,8 @@ extern const struct _mp_obj_module_t ustack_module;
     AUDIOBUSIO_MODULE \
     AUDIOCORE_MODULE \
     AUDIOIO_MODULE \
+    AUDIOMIXER_MODULE \
+    AUDIOMP3_MODULE \
     AUDIOPWMIO_MODULE \
     BITBANGIO_MODULE \
     BLEIO_MODULE \
@@ -603,8 +624,8 @@ extern const struct _mp_obj_module_t ustack_module;
       WIZNET_MODULE \
     PEW_MODULE \
     PIXELBUF_MODULE \
-    PULSEIO_MODULE \
     PS2IO_MODULE \
+    PULSEIO_MODULE \
     RANDOM_MODULE \
     RE_MODULE \
     ROTARYIO_MODULE \
@@ -647,21 +668,30 @@ extern const struct _mp_obj_module_t ustack_module;
     GAMEPAD_ROOT_POINTERS \
     mp_obj_t pew_singleton; \
     mp_obj_t terminal_tilegrid_tiles; \
-    BOARD_I2C_ROOT_POINTER \
     BOARD_UART_ROOT_POINTER \
     FLASH_ROOT_POINTERS \
     NETWORK_ROOT_POINTERS \
 
-void run_background_tasks(void);
+void supervisor_run_background_tasks_if_tick(void);
+#define RUN_BACKGROUND_TASKS (supervisor_run_background_tasks_if_tick())
 
 // TODO: Used in wiznet5k driver, but may not be needed in the long run.
 #define MICROPY_THREAD_YIELD()
 
-#define MICROPY_VM_HOOK_LOOP run_background_tasks();
-#define MICROPY_VM_HOOK_RETURN run_background_tasks();
+#define MICROPY_VM_HOOK_LOOP RUN_BACKGROUND_TASKS;
+#define MICROPY_VM_HOOK_RETURN RUN_BACKGROUND_TASKS;
 
+// CIRCUITPY_AUTORELOAD_DELAY_MS = 0 will completely disable autoreload.
+#ifndef CIRCUITPY_AUTORELOAD_DELAY_MS
 #define CIRCUITPY_AUTORELOAD_DELAY_MS 500
+#endif
+
+#ifndef CIRCUITPY_FILESYSTEM_FLUSH_INTERVAL_MS
 #define CIRCUITPY_FILESYSTEM_FLUSH_INTERVAL_MS 1000
+#endif
+
 #define CIRCUITPY_BOOT_OUTPUT_FILE "/boot_out.txt"
 
+#define CIRCUITPY_VERBOSE_BLE 0
+
 #endif  // __INCLUDED_MPCONFIG_CIRCUITPY_H
diff --git a/py/circuitpy_mpconfig.mk b/py/circuitpy_mpconfig.mk
index a408cd7ac..93175e136 100644
--- a/py/circuitpy_mpconfig.mk
+++ b/py/circuitpy_mpconfig.mk
@@ -23,7 +23,6 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 # THE SOFTWARE.
 
-
 # mpconfigboard.mk files can specify:
 # CIRCUITPY_FULL_BUILD = 1 (which is the default)
 # or
@@ -34,24 +33,35 @@
 ifndef CIRCUITPY_FULL_BUILD
   ifeq ($(CIRCUITPY_SMALL_BUILD),1)
     CIRCUITPY_FULL_BUILD = 0
-    CFLAGS += -DCIRCUITPY_FULL_BUILD=0
   else
     CIRCUITPY_FULL_BUILD = 1
-    CFLAGS += -DCIRCUITPY_FULL_BUILD=1
   endif
 endif
+CFLAGS += -DCIRCUITPY_FULL_BUILD=$(CIRCUITPY_FULL_BUILD)
 
 # Setting CIRCUITPY_MINIMAL_BUILD = 1 will disable all features
 # Use for for early stage or highly restricted ports
+ifndef CIRCUITPY_MINIMAL_BUILD
+CIRCUITPY_MINIMAL_BUILD = 0
+endif
+CFLAGS += -DCIRCUITPY_MINIMAL_BUILD=$(CIRCUITPY_MINIMAL_BUILD)
+
 ifndef CIRCUITPY_DEFAULT_BUILD
   ifeq ($(CIRCUITPY_MINIMAL_BUILD),1)
-  	CIRCUITPY_FULL_BUILD = 0
-  	CIRCUITPY_DEFAULT_BUILD = 0
+        CIRCUITPY_FULL_BUILD = 0
+        CIRCUITPY_DEFAULT_BUILD = 0
   else
-  	CIRCUITPY_DEFAULT_BUILD = 1
+        CIRCUITPY_DEFAULT_BUILD = 1
   endif
 endif
+CFLAGS += -DCIRCUITPY_DEFAULT_BUILD=$(CIRCUITPY_DEFAULT_BUILD)
 
+# Some features have no unique HAL component, and thus there's never
+# a reason to not include them.
+ifndef CIRCUITPY_ALWAYS_BUILD
+  CIRCUITPY_ALWAYS_BUILD = 1
+endif
+CFLAGS += -DCIRCUITPY_ALWAYS_BUILD=$(CIRCUITPY_ALWAYS_BUILD)
 
 
 # All builtin modules are listed below, with default values (0 for off, 1 for on)
@@ -74,6 +84,12 @@ CIRCUITPY_AUDIOIO = $(CIRCUITPY_FULL_BUILD)
 endif
 CFLAGS += -DCIRCUITPY_AUDIOIO=$(CIRCUITPY_AUDIOIO)
 
+ifndef CIRCUITPY_AUDIOIO_COMPAT
+CIRCUITPY_AUDIOIO_COMPAT = $(CIRCUITPY_AUDIOIO)
+endif
+CFLAGS += -DCIRCUITPY_AUDIOIO_COMPAT=$(CIRCUITPY_AUDIOIO_COMPAT)
+
+
 ifndef CIRCUITPY_AUDIOPWMIO
 CIRCUITPY_AUDIOPWMIO = 0
 endif
@@ -88,12 +104,26 @@ endif
 endif
 CFLAGS += -DCIRCUITPY_AUDIOCORE=$(CIRCUITPY_AUDIOCORE)
 
+ifndef CIRCUITPY_AUDIOMIXER
+CIRCUITPY_AUDIOMIXER = $(CIRCUITPY_AUDIOIO)
+endif
+CFLAGS += -DCIRCUITPY_AUDIOMIXER=$(CIRCUITPY_AUDIOMIXER)
+
+ifndef CIRCUITPY_AUDIOMP3
+ifeq ($(CIRCUITPY_FULL_BUILD),1)
+CIRCUITPY_AUDIOMP3 = $(CIRCUITPY_AUDIOCORE)
+else
+CIRCUITPY_AUDIOMP3 = 0
+endif
+endif
+CFLAGS += -DCIRCUITPY_AUDIOMP3=$(CIRCUITPY_AUDIOMP3)
+
 ifndef CIRCUITPY_BITBANGIO
 CIRCUITPY_BITBANGIO = $(CIRCUITPY_FULL_BUILD)
 endif
 CFLAGS += -DCIRCUITPY_BITBANGIO=$(CIRCUITPY_BITBANGIO)
 
-# Explicitly enabled for boards that support bleio.
+# Explicitly enabled for boards that support _bleio.
 ifndef CIRCUITPY_BLEIO
 CIRCUITPY_BLEIO = 0
 endif
@@ -140,7 +170,7 @@ endif
 CFLAGS += -DCIRCUITPY_I2CSLAVE=$(CIRCUITPY_I2CSLAVE)
 
 ifndef CIRCUITPY_MATH
-CIRCUITPY_MATH = $(CIRCUITPY_DEFAULT_BUILD)
+CIRCUITPY_MATH = $(CIRCUITPY_ALWAYS_BUILD)
 endif
 CFLAGS += -DCIRCUITPY_MATH=$(CIRCUITPY_MATH)
 
@@ -154,7 +184,7 @@ CIRCUITPY_NEOPIXEL_WRITE = $(CIRCUITPY_DEFAULT_BUILD)
 endif
 CFLAGS += -DCIRCUITPY_NEOPIXEL_WRITE=$(CIRCUITPY_NEOPIXEL_WRITE)
 
-# Only certain boards support NETWORK (Ethernet)
+# Enabled on SAMD51. Won't fit on SAMD21 builds. Not tested on nRF or STM32F4 builds.
 ifndef CIRCUITPY_NETWORK
 CIRCUITPY_NETWORK = 0
 endif
@@ -221,20 +251,26 @@ endif
 CFLAGS += -DCIRCUITPY_STORAGE=$(CIRCUITPY_STORAGE)
 
 ifndef CIRCUITPY_STRUCT
-CIRCUITPY_STRUCT = $(CIRCUITPY_DEFAULT_BUILD)
+CIRCUITPY_STRUCT = $(CIRCUITPY_ALWAYS_BUILD)
 endif
 CFLAGS += -DCIRCUITPY_STRUCT=$(CIRCUITPY_STRUCT)
 
 ifndef CIRCUITPY_SUPERVISOR
-CIRCUITPY_SUPERVISOR = $(CIRCUITPY_DEFAULT_BUILD)
+CIRCUITPY_SUPERVISOR = $(CIRCUITPY_ALWAYS_BUILD)
 endif
 CFLAGS += -DCIRCUITPY_SUPERVISOR=$(CIRCUITPY_SUPERVISOR)
 
 ifndef CIRCUITPY_TIME
-CIRCUITPY_TIME = $(CIRCUITPY_DEFAULT_BUILD)
+CIRCUITPY_TIME = $(CIRCUITPY_ALWAYS_BUILD)
 endif
 CFLAGS += -DCIRCUITPY_TIME=$(CIRCUITPY_TIME)
 
+# touchio might be native or generic. See circuitpy_defns.mk.
+ifndef CIRCUITPY_TOUCHIO_USE_NATIVE
+CIRCUITPY_TOUCHIO_USE_NATIVE = 0
+endif
+CFLAGS += -DCIRCUITPY_TOUCHIO_USE_NATIVE=$(CIRCUITPY_TOUCHIO_USE_NATIVE)
+
 ifndef CIRCUITPY_TOUCHIO
 CIRCUITPY_TOUCHIO = $(CIRCUITPY_DEFAULT_BUILD)
 endif
@@ -266,3 +302,35 @@ ifndef CIRCUITPY_USTACK
 CIRCUITPY_USTACK = 0
 endif
 CFLAGS += -DCIRCUITPY_USTACK=$(CIRCUITPY_USTACK)
+
+# Non-module conditionals
+
+ifndef CIRCUITPY_BITBANG_APA102
+CIRCUITPY_BITBANG_APA102 = 0
+endif
+CFLAGS += -DCIRCUITPY_BITBANG_APA102=$(CIRCUITPY_BITBANG_APA102)
+
+# Should busio.I2C() check for pullups?
+# Some boards in combination with certain peripherals may not want this.
+ifndef CIRCUITPY_REQUIRE_I2C_PULLUPS
+CIRCUITPY_REQUIRE_I2C_PULLUPS = 1
+endif
+CFLAGS += -DCIRCUITPY_REQUIRE_I2C_PULLUPS=$(CIRCUITPY_REQUIRE_I2C_PULLUPS)
+
+# REPL over BLE
+ifndef CIRCUITPY_SERIAL_BLE
+CIRCUITPY_SERIAL_BLE = 0
+endif
+CFLAGS += -DCIRCUITPY_SERIAL_BLE=$(CIRCUITPY_SERIAL_BLE)
+
+# REPL over UART
+ifndef CIRCUITPY_SERIAL_UART
+CIRCUITPY_SERIAL_UART = 0
+endif
+CFLAGS += -DCIRCUITPY_SERIAL_UART=$(CIRCUITPY_SERIAL_UART)
+
+# Enabled micropython.native decorator (experimental)
+ifndef CIRCUITPY_ENABLE_MPY_NATIVE
+CIRCUITPY_ENABLE_MPY_NATIVE = 0
+endif
+CFLAGS += -DCIRCUITPY_ENABLE_MPY_NATIVE=$(CIRCUITPY_ENABLE_MPY_NATIVE)
diff --git a/py/compile.c b/py/compile.c
index 1218aa07e..77715d3fe 100644
--- a/py/compile.c
+++ b/py/compile.c
@@ -775,13 +775,22 @@ STATIC bool compile_built_in_decorator(compiler_t *comp, int name_len, mp_parse_
     qstr attr = MP_PARSE_NODE_LEAF_ARG(name_nodes[1]);
     if (attr == MP_QSTR_bytecode) {
         *emit_options = MP_EMIT_OPT_BYTECODE;
-#if MICROPY_EMIT_NATIVE
+    // @micropython.native decorator.
     } else if (attr == MP_QSTR_native) {
+        // Different from MicroPython: native doesn't raise SyntaxError if native support isn't
+        // compiled, it just passes through the function unmodified.
+        #if MICROPY_EMIT_NATIVE
         *emit_options = MP_EMIT_OPT_NATIVE_PYTHON;
+        #else
+        return true;
+        #endif
+    #if MICROPY_EMIT_NATIVE
+    // @micropython.viper decorator.
     } else if (attr == MP_QSTR_viper) {
         *emit_options = MP_EMIT_OPT_VIPER;
-#endif
+    #endif
     #if MICROPY_EMIT_INLINE_ASM
+    // @micropython.asm_thumb decorator.
     } else if (attr == ASM_DECORATOR_QSTR) {
         *emit_options = MP_EMIT_OPT_ASM;
     #endif
@@ -3207,7 +3216,7 @@ STATIC void compile_scope_inline_asm(compiler_t *comp, scope_t *scope, pass_kind
             }
             if (pass > MP_PASS_SCOPE) {
                 mp_int_t bytesize = MP_PARSE_NODE_LEAF_SMALL_INT(pn_arg[0]);
-                for (uint j = 1; j < n_args; j++) {
+                for (int j = 1; j < n_args; j++) {
                     if (!MP_PARSE_NODE_IS_SMALL_INT(pn_arg[j])) {
                         compile_syntax_error(comp, nodes[i], translate("'data' requires integer arguments"));
                         return;
diff --git a/py/emitnative.c b/py/emitnative.c
index 67b0025c6..6d23bf097 100644
--- a/py/emitnative.c
+++ b/py/emitnative.c
@@ -58,6 +58,22 @@
 #define DEBUG_printf(...) (void)0
 #endif
 
+#ifndef N_X64
+    #define N_X64 (0)
+#endif
+#ifndef N_X86
+    #define N_X86 (0)
+#endif
+#ifndef N_THUMB
+    #define N_THUMB (0)
+#endif
+#ifndef N_ARM
+    #define N_ARM (0)
+#endif
+#ifndef N_XTENSA
+    #define N_XTENSA (0)
+#endif
+
 // wrapper around everything in this file
 #if N_X64 || N_X86 || N_THUMB || N_ARM || N_XTENSA
 
@@ -443,10 +459,12 @@ STATIC void emit_native_end_pass(emit_t *emit) {
             type_sig |= (emit->local_vtype[i] & 0xf) << (i * 4 + 4);
         }
 
+        #pragma GCC diagnostic ignored "-Wcast-align"
         mp_emit_glue_assign_native(emit->scope->raw_code,
             emit->do_viper_types ? MP_CODE_NATIVE_VIPER : MP_CODE_NATIVE_PY,
             f, f_len, (mp_uint_t*)((byte*)f + emit->const_table_offset),
             emit->scope->num_pos_args, emit->scope->scope_flags, type_sig);
+        #pragma GCC diagnostic pop
     }
 }
 
diff --git a/py/gc.c b/py/gc.c
index 10b36950c..fef67f61b 100755
--- a/py/gc.c
+++ b/py/gc.c
@@ -53,9 +53,6 @@
 // detect untraced object still in use
 #define CLEAR_ON_SWEEP (0)
 
-#define WORDS_PER_BLOCK ((MICROPY_BYTES_PER_GC_BLOCK) / BYTES_PER_WORD)
-#define BYTES_PER_BLOCK (MICROPY_BYTES_PER_GC_BLOCK)
-
 // ATB = allocation table byte
 // 0b00 = FREE -- free block
 // 0b01 = HEAD -- head of a chain of blocks
@@ -209,13 +206,6 @@ bool gc_is_locked(void) {
     return MP_STATE_MEM(gc_lock_depth) != 0;
 }
 
-// ptr should be of type void*
-#define VERIFY_PTR(ptr) ( \
-        ((uintptr_t)(ptr) & (BYTES_PER_BLOCK - 1)) == 0      /* must be aligned on a block */ \
-        && ptr >= (void*)MP_STATE_MEM(gc_pool_start)     /* must be above start of pool */ \
-        && ptr < (void*)MP_STATE_MEM(gc_pool_end)        /* must be below end of pool */ \
-    )
-
 #ifndef TRACE_MARK
 #if DEBUG_PRINT
 #define TRACE_MARK(block, ptr) DEBUG_printf("gc_mark(%p)\n", ptr)
@@ -474,6 +464,10 @@ void gc_info(gc_info_t *info) {
     GC_EXIT();
 }
 
+bool gc_alloc_possible(void) {
+    return MP_STATE_MEM(gc_pool_start) != 0;
+}
+
 // We place long lived objects at the end of the heap rather than the start. This reduces
 // fragmentation by localizing the heap churn to one portion of memory (the start of the heap.)
 void *gc_alloc(size_t n_bytes, bool has_finaliser, bool long_lived) {
@@ -509,7 +503,6 @@ void *gc_alloc(size_t n_bytes, bool has_finaliser, bool long_lived) {
         gc_collect();
         collected = 1;
         GC_ENTER();
-        collected = true;
     }
     #endif
 
@@ -678,6 +671,9 @@ void gc_free(void *ptr) {
     if (ptr == NULL) {
         GC_EXIT();
     } else {
+        if (MP_STATE_MEM(gc_pool_start) == 0) {
+            reset_into_safe_mode(GC_ALLOC_OUTSIDE_VM);
+        }
         // get the GC block number corresponding to this pointer
         assert(VERIFY_PTR(ptr));
         size_t block = BLOCK_FROM_PTR(ptr);
diff --git a/py/gc.h b/py/gc.h
index 02bf45158..2a0811f4e 100644
--- a/py/gc.h
+++ b/py/gc.h
@@ -29,8 +29,19 @@
 #include <stdint.h>
 
 #include "py/mpconfig.h"
+#include "py/mpstate.h"
 #include "py/misc.h"
 
+#define WORDS_PER_BLOCK ((MICROPY_BYTES_PER_GC_BLOCK) / BYTES_PER_WORD)
+#define BYTES_PER_BLOCK (MICROPY_BYTES_PER_GC_BLOCK)
+
+// ptr should be of type void*
+#define VERIFY_PTR(ptr) ( \
+        ((uintptr_t)(ptr) & (BYTES_PER_BLOCK - 1)) == 0      /* must be aligned on a block */ \
+        && ptr >= (void*)MP_STATE_MEM(gc_pool_start)     /* must be above start of pool */ \
+        && ptr < (void*)MP_STATE_MEM(gc_pool_end)        /* must be below end of pool */ \
+    )
+
 void gc_init(void *start, void *end);
 void gc_deinit(void);
 
@@ -47,6 +58,8 @@ void gc_collect_ptr(void *ptr);
 void gc_collect_root(void **ptrs, size_t len);
 void gc_collect_end(void);
 
+// Is the gc heap available?
+bool gc_alloc_possible(void);
 void *gc_alloc(size_t n_bytes, bool has_finaliser, bool long_lived);
 
 // Use this function to sweep the whole heap and run all finalisers
diff --git a/py/gc_long_lived.c b/py/gc_long_lived.c
index 49bf1fcd7..01c22a7af 100755
--- a/py/gc_long_lived.c
+++ b/py/gc_long_lived.c
@@ -126,6 +126,11 @@ mp_obj_t make_obj_long_lived(mp_obj_t obj, uint8_t max_depth){
     if (obj == NULL) {
         return obj;
     }
+    // If not in the GC pool, do nothing. This can happen (at least) when
+    // there are frozen mp_type_bytes objects in ROM.
+    if (!VERIFY_PTR((void *)obj)) {
+        return obj;
+    }
     if (MP_OBJ_IS_TYPE(obj, &mp_type_fun_bc)) {
         mp_obj_fun_bc_t *fun_bc = MP_OBJ_TO_PTR(obj);
         return MP_OBJ_FROM_PTR(make_fun_bc_long_lived(fun_bc, max_depth));
diff --git a/py/makeqstrdata.py b/py/makeqstrdata.py
index 8e3835d86..0d667959d 100644
--- a/py/makeqstrdata.py
+++ b/py/makeqstrdata.py
@@ -103,14 +103,10 @@ def compute_huffman_coding(translations, qstrs, compression_filename):
     # go through each qstr and print it out
     for _, _, qstr in qstrs.values():
         all_strings.append(qstr)
-    all_strings_concat = "".join(all_strings).encode("utf-8")
+    all_strings_concat = "".join(all_strings)
     counts = collections.Counter(all_strings_concat)
-    # add other values
-    for i in range(256):
-        if i not in counts:
-            counts[i] = 0
     cb = huffman.codebook(counts.items())
-    values = bytearray()
+    values = []
     length_count = {}
     renumbered = 0
     last_l = None
@@ -124,26 +120,27 @@ def compute_huffman_coding(translations, qstrs, compression_filename):
         if last_l:
             renumbered <<= (l - last_l)
         canonical[ch] = '{0:0{width}b}'.format(renumbered, width=l)
-        if chr(ch) in C_ESCAPES:
-            s = C_ESCAPES[chr(ch)]
-        else:
-            s = chr(ch)
-        print("//", ch, s, counts[ch], canonical[ch], renumbered)
+        s = C_ESCAPES.get(ch, ch)
+        print("//", ord(ch), s, counts[ch], canonical[ch], renumbered)
         renumbered += 1
         last_l = l
     lengths = bytearray()
-    for i in range(1, max(length_count) + 1):
+    print("// length count", length_count)
+    for i in range(1, max(length_count) + 2):
         lengths.append(length_count.get(i, 0))
+    print("// values", values, "lengths", len(lengths), lengths)
+    print("// estimated total memory size", len(lengths) + 2*len(values) + sum(len(cb[u]) for u in all_strings_concat))
     print("//", values, lengths)
+    values_type = "uint16_t" if max(ord(u) for u in values) > 255 else "uint8_t"
     with open(compression_filename, "w") as f:
         f.write("const uint8_t lengths[] = {{ {} }};\n".format(", ".join(map(str, lengths))))
-        f.write("const uint8_t values[256] = {{ {} }};\n".format(", ".join(map(str, values))))
+        f.write("const {} values[] = {{ {} }};\n".format(values_type, ", ".join(str(ord(u)) for u in values)))
     return values, lengths
 
 def decompress(encoding_table, length, encoded):
     values, lengths = encoding_table
     #print(l, encoded)
-    dec = bytearray(length)
+    dec = []
     this_byte = 0
     this_bit = 7
     b = encoded[this_byte]
@@ -173,14 +170,14 @@ def decompress(encoding_table, length, encoded):
             searched_length += lengths[bit_length]
 
         v = values[searched_length + bits - max_code]
-        dec[i] = v
-    return dec
+        dec.append(v)
+    return ''.join(dec)
 
 def compress(encoding_table, decompressed):
-    if not isinstance(decompressed, bytes):
+    if not isinstance(decompressed, str):
         raise TypeError()
     values, lengths = encoding_table
-    enc = bytearray(len(decompressed) * 2)
+    enc = bytearray(len(decompressed) * 3)
     #print(decompressed)
     #print(lengths)
     current_bit = 7
@@ -228,7 +225,7 @@ def compress(encoding_table, decompressed):
     if current_bit != 7:
         current_byte += 1
     if current_byte > len(decompressed):
-        print("Note: compression increased length", repr(decompressed.decode('utf-8')), len(decompressed), current_byte, file=sys.stderr)
+        print("Note: compression increased length", repr(decompressed), len(decompressed), current_byte, file=sys.stderr)
     return enc[:current_byte]
 
 def qstr_escape(qst):
@@ -347,9 +344,9 @@ def print_qstr_data(encoding_table, qcfgs, qstrs, i18ns):
     total_text_compressed_size = 0
     for original, translation in i18ns:
         translation_encoded = translation.encode("utf-8")
-        compressed = compress(encoding_table, translation_encoded)
+        compressed = compress(encoding_table, translation)
         total_text_compressed_size += len(compressed)
-        decompressed = decompress(encoding_table, len(translation_encoded), compressed).decode("utf-8")
+        decompressed = decompress(encoding_table, len(translation_encoded), compressed)
         for c in C_ESCAPES:
             decompressed = decompressed.replace(c, C_ESCAPES[c])
         print("TRANSLATION(\"{}\", {}, {{ {} }}) // {}".format(original, len(translation_encoded)+1, ", ".join(["0x{:02x}".format(x) for x in compressed]), decompressed))
diff --git a/py/modio.c b/py/modio.c
index d7c1a58a8..17840a6d8 100644
--- a/py/modio.c
+++ b/py/modio.c
@@ -90,6 +90,7 @@ STATIC mp_uint_t iobase_ioctl(mp_obj_t obj, mp_uint_t request, uintptr_t arg, in
 }
 
 STATIC const mp_stream_p_t iobase_p = {
+    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_stream)
     .read = iobase_read,
     .write = iobase_write,
     .ioctl = iobase_ioctl,
@@ -185,6 +186,7 @@ STATIC const mp_rom_map_elem_t bufwriter_locals_dict_table[] = {
 STATIC MP_DEFINE_CONST_DICT(bufwriter_locals_dict, bufwriter_locals_dict_table);
 
 STATIC const mp_stream_p_t bufwriter_stream_p = {
+    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_stream)
     .write = bufwriter_write,
 };
 
diff --git a/py/mpconfig.h b/py/mpconfig.h
index 3ec383817..a0d211bfa 100755
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -1440,6 +1440,15 @@ typedef double mp_float_t;
 #define MP_UNLIKELY(x) __builtin_expect((x), 0)
 #endif
 
+// To annotate that code is unreachable
+#ifndef MP_UNREACHABLE
+#if defined(__GNUC__)
+#define MP_UNREACHABLE __builtin_unreachable();
+#else
+#define MP_UNREACHABLE for (;;);
+#endif
+#endif
+
 #ifndef MP_HTOBE16
 #if MP_ENDIANNESS_LITTLE
 # define MP_HTOBE16(x) ((uint16_t)( (((x) & 0xff) << 8) | (((x) >> 8) & 0xff) ))
diff --git a/py/nlr.h b/py/nlr.h
index 802f5f39a..1b95002d3 100644
--- a/py/nlr.h
+++ b/py/nlr.h
@@ -36,33 +36,45 @@
 
 // If MICROPY_NLR_SETJMP is not enabled then auto-detect the machine arch
 #if !defined(MICROPY_NLR_SETJMP) || !MICROPY_NLR_SETJMP
-#define MICROPY_NLR_SETJMP (0)
 // A lot of nlr-related things need different treatment on Windows
-#if defined(_WIN32) || defined(__CYGWIN__)
-#define MICROPY_NLR_OS_WINDOWS 1
-#else
-#define MICROPY_NLR_OS_WINDOWS 0
-#endif
-#if defined(__i386__)
-    #define MICROPY_NLR_X86 (1)
-    #define MICROPY_NLR_NUM_REGS (6)
-#elif defined(__x86_64__)
-    #define MICROPY_NLR_X64 (1)
-    #if MICROPY_NLR_OS_WINDOWS
-        #define MICROPY_NLR_NUM_REGS (10)
+    #if defined(_WIN32) || defined(__CYGWIN__)
+        #define MICROPY_NLR_OS_WINDOWS 1
     #else
-        #define MICROPY_NLR_NUM_REGS (8)
+        #define MICROPY_NLR_OS_WINDOWS 0
     #endif
-#elif defined(__thumb2__) || defined(__thumb__) || defined(__arm__)
-    #define MICROPY_NLR_THUMB (1)
-    #define MICROPY_NLR_NUM_REGS (10)
-#elif defined(__xtensa__)
-    #define MICROPY_NLR_XTENSA (1)
-    #define MICROPY_NLR_NUM_REGS (10)
-#else
-    #define MICROPY_NLR_SETJMP (1)
+    #if defined(__i386__)
+        #define MICROPY_NLR_X86 (1)
+        #define MICROPY_NLR_NUM_REGS (6)
+    #elif defined(__x86_64__)
+        #define MICROPY_NLR_X64 (1)
+        #if MICROPY_NLR_OS_WINDOWS
+            #define MICROPY_NLR_NUM_REGS (10)
+        #else
+            #define MICROPY_NLR_NUM_REGS (8)
+        #endif
+    #elif defined(__thumb2__) || defined(__thumb__) || defined(__arm__)
+        #define MICROPY_NLR_THUMB (1)
+        #if defined(__SOFTFP__)
+            #define MICROPY_NLR_NUM_REGS (10)
+        #else
+            // With hardware FP registers s16-s31 are callee save so in principle
+            // should be saved and restored by the NLR code.  gcc only uses s16-s21
+            // so only save/restore those as an optimisation.
+            #define MICROPY_NLR_NUM_REGS (10 + 6)
+        #endif
+    #elif defined(__xtensa__)
+        #define MICROPY_NLR_XTENSA (1)
+        #define MICROPY_NLR_NUM_REGS (10)
+    #else
+        #define MICROPY_NLR_SETJMP (1)
     //#warning "No native NLR support for this arch, using setjmp implementation"
+    #endif
 #endif
+
+// If MICROPY_NLR_SETJMP is not defined above -  define/disable it here
+
+#if !defined(MICROPY_NLR_SETJMP)
+    #define MICROPY_NLR_SETJMP (0)
 #endif
 
 #if MICROPY_NLR_SETJMP
diff --git a/py/nlrthumb.c b/py/nlrthumb.c
index 69d3f868a..056aa358e 100644
--- a/py/nlrthumb.c
+++ b/py/nlrthumb.c
@@ -63,6 +63,11 @@ __attribute__((naked)) unsigned int nlr_push(nlr_buf_t *nlr) {
     "str    r10, [r0, #36]      \n" // store r10 into nlr_buf
     "str    r11, [r0, #40]      \n" // store r11 into nlr_buf
     "str    r13, [r0, #44]      \n" // store r13=sp into nlr_buf
+    #if MICROPY_NLR_NUM_REGS == 16
+    "vstr   d8, [r0, #48]       \n" // store s16-s17 into nlr_buf
+    "vstr   d9, [r0, #56]       \n" // store s18-s19 into nlr_buf
+    "vstr   d10, [r0, #64]      \n" // store s20-s21 into nlr_buf
+    #endif
     "str    lr, [r0, #8]        \n" // store lr into nlr_buf
 #endif
 
@@ -118,6 +123,11 @@ NORETURN void nlr_jump(void *val) {
     "ldr    r10, [r0, #36]      \n" // load r10 from nlr_buf
     "ldr    r11, [r0, #40]      \n" // load r11 from nlr_buf
     "ldr    r13, [r0, #44]      \n" // load r13=sp from nlr_buf
+    #if MICROPY_NLR_NUM_REGS == 16
+    "vldr   d8, [r0, #48]       \n" // load s16-s17 from nlr_buf
+    "vldr   d9, [r0, #56]       \n" // load s18-s19 from nlr_buf
+    "vldr   d10, [r0, #64]      \n" // load s20-s21 from nlr_buf
+    #endif
     "ldr    lr, [r0, #8]        \n" // load lr from nlr_buf
 #endif
     "movs   r0, #1              \n" // return 1, non-local return
@@ -127,11 +137,7 @@ NORETURN void nlr_jump(void *val) {
     :                               // clobbered registers
     );
 
-    #if defined(__GNUC__)
-    __builtin_unreachable();
-    #else
-    for (;;); // needed to silence compiler warning
-    #endif
+    MP_UNREACHABLE
 }
 
 #endif // MICROPY_NLR_THUMB
diff --git a/py/nlrx64.c b/py/nlrx64.c
index 9b2b22c22..569ad84fb 100644
--- a/py/nlrx64.c
+++ b/py/nlrx64.c
@@ -108,7 +108,7 @@ NORETURN void nlr_jump(void *val) {
     :                               // clobbered registers
     );
 
-    for (;;); // needed to silence compiler warning
+    MP_UNREACHABLE
 }
 
 #endif // MICROPY_NLR_X64
diff --git a/py/nlrx86.c b/py/nlrx86.c
index 4900a4c0d..6fbbe4432 100644
--- a/py/nlrx86.c
+++ b/py/nlrx86.c
@@ -100,7 +100,7 @@ NORETURN void nlr_jump(void *val) {
     :                               // clobbered registers
     );
 
-    for (;;); // needed to silence compiler warning
+    MP_UNREACHABLE
 }
 
 #endif // MICROPY_NLR_X86
diff --git a/py/nlrxtensa.c b/py/nlrxtensa.c
index d66c7a9a7..564035004 100644
--- a/py/nlrxtensa.c
+++ b/py/nlrxtensa.c
@@ -77,7 +77,7 @@ NORETURN void nlr_jump(void *val) {
     :                               // clobbered registers
     );
 
-    for (;;); // needed to silence compiler warning
+    MP_UNREACHABLE
 }
 
 #endif // MICROPY_NLR_XTENSA
diff --git a/py/obj.c b/py/obj.c
index 322a302f9..09e71be4d 100644
--- a/py/obj.c
+++ b/py/obj.c
@@ -63,6 +63,9 @@ const char *mp_obj_get_type_str(mp_const_obj_t o_in) {
 void mp_obj_print_helper(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
     // There can be data structures nested too deep, or just recursive
     MP_STACK_CHECK();
+    #ifdef RUN_BACKGROUND_TASKS
+    RUN_BACKGROUND_TASKS;
+    #endif
 #ifndef NDEBUG
     if (o_in == MP_OBJ_NULL) {
         mp_print_str(print, "(nil)");
@@ -486,6 +489,7 @@ mp_obj_t mp_obj_len_maybe(mp_obj_t o_in) {
 
 mp_obj_t mp_obj_subscr(mp_obj_t base, mp_obj_t index, mp_obj_t value) {
     mp_obj_type_t *type = mp_obj_get_type(base);
+
     if (type->subscr != NULL) {
         mp_obj_t ret = type->subscr(base, index, value);
         // May have called port specific C code. Make sure it didn't mess up the heap.
@@ -493,7 +497,6 @@ mp_obj_t mp_obj_subscr(mp_obj_t base, mp_obj_t index, mp_obj_t value) {
         if (ret != MP_OBJ_NULL) {
             return ret;
         }
-        // TODO: call base classes here?
     }
     if (value == MP_OBJ_NULL) {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
diff --git a/py/obj.h b/py/obj.h
index 6eead377d..cf4216d02 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -647,6 +647,7 @@ mp_obj_t mp_obj_new_str(const char* data, size_t len);
 mp_obj_t mp_obj_new_str_via_qstr(const char* data, size_t len);
 mp_obj_t mp_obj_new_str_from_vstr(const mp_obj_type_t *type, vstr_t *vstr);
 mp_obj_t mp_obj_new_bytes(const byte* data, size_t len);
+mp_obj_t mp_obj_new_bytes_of_zeros(size_t len);
 mp_obj_t mp_obj_new_bytearray(size_t n, void *items);
 mp_obj_t mp_obj_new_bytearray_of_zeros(size_t n);
 mp_obj_t mp_obj_new_bytearray_by_ref(size_t n, void *items);
@@ -668,6 +669,7 @@ mp_obj_t mp_obj_new_gen_wrap(mp_obj_t fun);
 mp_obj_t mp_obj_new_closure(mp_obj_t fun, size_t n_closed, const mp_obj_t *closed);
 mp_obj_t mp_obj_new_tuple(size_t n, const mp_obj_t *items);
 mp_obj_t mp_obj_new_list(size_t n, mp_obj_t *items);
+mp_obj_t mp_obj_new_list_from_iter(mp_obj_t iterable);
 mp_obj_t mp_obj_new_dict(size_t n_args);
 mp_obj_t mp_obj_new_set(size_t n_args, mp_obj_t *items);
 mp_obj_t mp_obj_new_slice(mp_obj_t start, mp_obj_t stop, mp_obj_t step);
diff --git a/py/objfun.c b/py/objfun.c
index b8364815b..7e5899456 100644
--- a/py/objfun.c
+++ b/py/objfun.c
@@ -546,7 +546,7 @@ STATIC mp_uint_t convert_obj_for_inline_asm(mp_obj_t obj) {
 STATIC mp_obj_t fun_asm_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_fun_asm_t *self = self_in;
 
-    mp_arg_check_num(n_args, n_kw, self->n_args, self->n_args, false);
+    mp_arg_check_num_kw_array(n_args, n_kw, self->n_args, self->n_args, false);
 
     void *fun = MICROPY_MAKE_POINTER_CALLABLE(self->fun_data);
 
diff --git a/py/objlist.c b/py/objlist.c
index 558c4c611..b32f82085 100644
--- a/py/objlist.c
+++ b/py/objlist.c
@@ -68,6 +68,11 @@ STATIC mp_obj_t list_extend_from_iter(mp_obj_t list, mp_obj_t iterable) {
     return list;
 }
 
+mp_obj_t mp_obj_new_list_from_iter(mp_obj_t iterable) {
+    mp_obj_t list = mp_obj_new_list(0, NULL);
+    return list_extend_from_iter(list, iterable);
+}
+
 STATIC mp_obj_t list_make_new(const mp_obj_type_t *type_in, size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
     (void)type_in;
     mp_arg_check_num(n_args, kw_args, 0, 1, false);
@@ -154,11 +159,11 @@ STATIC mp_obj_t list_binary_op(mp_binary_op_t op, mp_obj_t lhs, mp_obj_t rhs) {
 }
 
 STATIC mp_obj_t list_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
+    mp_obj_list_t *self = mp_instance_cast_to_native_base(self_in, &mp_type_list);
     if (value == MP_OBJ_NULL) {
         // delete
 #if MICROPY_PY_BUILTINS_SLICE
         if (MP_OBJ_IS_TYPE(index, &mp_type_slice)) {
-            mp_obj_list_t *self = MP_OBJ_TO_PTR(self_in);
             mp_bound_slice_t slice;
             if (!mp_seq_get_fast_slice_indexes(self->len, index, &slice)) {
                 mp_raise_NotImplementedError(NULL);
@@ -174,12 +179,11 @@ STATIC mp_obj_t list_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
             return mp_const_none;
         }
 #endif
-        mp_obj_t args[2] = {self_in, index};
+        mp_obj_t args[2] = {self, index};
         list_pop(2, args);
         return mp_const_none;
     } else if (value == MP_OBJ_SENTINEL) {
         // load
-        mp_obj_list_t *self = MP_OBJ_TO_PTR(self_in);
 #if MICROPY_PY_BUILTINS_SLICE
         if (MP_OBJ_IS_TYPE(index, &mp_type_slice)) {
             mp_bound_slice_t slice;
@@ -196,7 +200,6 @@ STATIC mp_obj_t list_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
     } else {
 #if MICROPY_PY_BUILTINS_SLICE
         if (MP_OBJ_IS_TYPE(index, &mp_type_slice)) {
-            mp_obj_list_t *self = MP_OBJ_TO_PTR(self_in);
             size_t value_len; mp_obj_t *value_items;
             mp_obj_get_array(value, &value_len, &value_items);
             mp_bound_slice_t slice_out;
@@ -225,7 +228,7 @@ STATIC mp_obj_t list_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
             return mp_const_none;
         }
 #endif
-        mp_obj_list_store(self_in, index, value);
+        mp_obj_list_store(self, index, value);
         return mp_const_none;
     }
 }
diff --git a/py/objnamedtuple.c b/py/objnamedtuple.c
index a044fe3ff..84dcf7909 100644
--- a/py/objnamedtuple.c
+++ b/py/objnamedtuple.c
@@ -31,6 +31,7 @@
 #include "py/runtime.h"
 #include "py/objstr.h"
 #include "py/objnamedtuple.h"
+#include "py/objtype.h"
 
 #include "supervisor/shared/translate.h"
 
diff --git a/py/objstr.c b/py/objstr.c
index ebd11d5cc..fde264681 100644
--- a/py/objstr.c
+++ b/py/objstr.c
@@ -31,6 +31,7 @@
 #include "py/unicode.h"
 #include "py/objstr.h"
 #include "py/objlist.h"
+#include "py/objtype.h"
 #include "py/runtime.h"
 #include "py/stackctrl.h"
 
@@ -41,6 +42,12 @@ STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, size_t n_args, const mp_obj_
 STATIC mp_obj_t mp_obj_new_bytes_iterator(mp_obj_t str, mp_obj_iter_buf_t *iter_buf);
 STATIC NORETURN void bad_implicit_conversion(mp_obj_t self_in);
 
+const char nibble_to_hex_upper[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+                                      'A', 'B', 'C', 'D', 'E', 'F'};
+
+const char nibble_to_hex_lower[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+                                      'a', 'b', 'c', 'd', 'e', 'f'};
+
 /******************************************************************************/
 /* str                                                                        */
 
@@ -220,10 +227,6 @@ STATIC mp_obj_t bytes_make_new(const mp_obj_type_t *type_in, size_t n_args, cons
         return MP_OBJ_FROM_PTR(o);
     }
 
-    if (n_args > 1) {
-        goto wrong_args;
-    }
-
     if (MP_OBJ_IS_SMALL_INT(args[0])) {
         mp_int_t len = MP_OBJ_SMALL_INT_VALUE(args[0]);
         if (len < 0) {
@@ -235,6 +238,17 @@ STATIC mp_obj_t bytes_make_new(const mp_obj_type_t *type_in, size_t n_args, cons
         return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
     }
 
+    if (n_args > 1) {
+        goto wrong_args;
+    }
+
+    // check if __bytes__ exists, and if so delegate to it
+    mp_obj_t dest[2];
+    mp_load_method_maybe(args[0], MP_QSTR___bytes__, dest);
+    if (dest[0] != MP_OBJ_NULL) {
+        return mp_call_method_n_kw(0, 0, dest);
+    }
+
     // check if argument has the buffer protocol
     mp_buffer_info_t bufinfo;
     if (mp_get_buffer(args[0], &bufinfo, MP_BUFFER_READ)) {
@@ -2088,6 +2102,14 @@ mp_obj_t mp_obj_new_bytes(const byte* data, size_t len) {
     return mp_obj_new_str_copy(&mp_type_bytes, data, len);
 }
 
+mp_obj_t mp_obj_new_bytes_of_zeros(size_t len) {
+    vstr_t vstr;
+    vstr_init_len(&vstr, len);
+    memset(vstr.buf, 0, len);
+    return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
+}
+
+
 bool mp_obj_str_equal(mp_obj_t s1, mp_obj_t s2) {
     if (MP_OBJ_IS_QSTR(s1) && MP_OBJ_IS_QSTR(s2)) {
         return s1 == s2;
diff --git a/py/objstr.h b/py/objstr.h
index 0efe62a80..61a11d0bd 100644
--- a/py/objstr.h
+++ b/py/objstr.h
@@ -77,6 +77,9 @@ const byte *str_index_to_ptr(const mp_obj_type_t *type, const byte *self_data, s
                              mp_obj_t index, bool is_slice);
 const byte *find_subbytes(const byte *haystack, size_t hlen, const byte *needle, size_t nlen, int direction);
 
+const char nibble_to_hex_upper[16];
+const char nibble_to_hex_lower[16];
+
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(str_encode_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(str_find_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(str_rfind_obj);
diff --git a/py/objstringio.c b/py/objstringio.c
index d2ca6decd..178e6446c 100644
--- a/py/objstringio.c
+++ b/py/objstringio.c
@@ -240,6 +240,7 @@ STATIC const mp_rom_map_elem_t stringio_locals_dict_table[] = {
 STATIC MP_DEFINE_CONST_DICT(stringio_locals_dict, stringio_locals_dict_table);
 
 STATIC const mp_stream_p_t stringio_stream_p = {
+    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_stream)
     .read = stringio_read,
     .write = stringio_write,
     .ioctl = stringio_ioctl,
@@ -247,6 +248,7 @@ STATIC const mp_stream_p_t stringio_stream_p = {
 };
 
 STATIC const mp_stream_p_t bytesio_stream_p = {
+    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_stream)
     .read = stringio_read,
     .write = stringio_write,
     .ioctl = stringio_ioctl,
diff --git a/py/objtuple.c b/py/objtuple.c
index 474f81c1a..0a2ed6f4c 100644
--- a/py/objtuple.c
+++ b/py/objtuple.c
@@ -29,6 +29,7 @@
 
 #include "py/objtuple.h"
 #include "py/runtime.h"
+#include "py/objtype.h"
 
 #include "supervisor/shared/translate.h"
 
@@ -181,6 +182,11 @@ mp_obj_t mp_obj_tuple_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
     if (value == MP_OBJ_SENTINEL) {
         // load
         mp_obj_tuple_t *self = MP_OBJ_TO_PTR(self_in);
+        // when called with a native type (eg namedtuple) using mp_obj_tuple_subscr, get the native self
+        if (self->base.type->subscr != &mp_obj_tuple_subscr) {
+            self = mp_instance_cast_to_native_base(self_in, &mp_type_tuple);
+        }
+
 #if MICROPY_PY_BUILTINS_SLICE
         if (MP_OBJ_IS_TYPE(index, &mp_type_slice)) {
             mp_bound_slice_t slice;
@@ -251,7 +257,8 @@ mp_obj_t mp_obj_new_tuple(size_t n, const mp_obj_t *items) {
 }
 
 void mp_obj_tuple_get(mp_obj_t self_in, size_t *len, mp_obj_t **items) {
-    assert(MP_OBJ_IS_TYPE(self_in, &mp_type_tuple));
+    // type check is done on getiter method to allow tuple, namedtuple, attrtuple
+    mp_check_self(mp_obj_get_type(self_in)->getiter == mp_obj_tuple_getiter);
     mp_obj_tuple_t *self = MP_OBJ_TO_PTR(self_in);
     *len = self->len;
     *items = &self->items[0];
diff --git a/py/objtype.c b/py/objtype.c
index 5133d849f..a5e733208 100644
--- a/py/objtype.c
+++ b/py/objtype.c
@@ -34,6 +34,7 @@
 #include "py/objtype.h"
 #include "py/runtime.h"
 
+#include "supervisor/shared/stack.h"
 #include "supervisor/shared/translate.h"
 
 #if MICROPY_DEBUG_VERBOSE // print debugging info
@@ -336,8 +337,10 @@ mp_obj_t mp_obj_instance_make_new(const mp_obj_type_t *self, size_t n_args, cons
             mp_obj_t *args2 = m_new(mp_obj_t, 1 + n_args + 2 * n_kw);
             args2[0] = MP_OBJ_FROM_PTR(self);
             memcpy(args2 + 1, args, n_args * sizeof(mp_obj_t));
-            // copy in kwargs
-            memcpy(args2 + 1 + n_args, kw_args->table, 2 * n_kw * sizeof(mp_obj_t));
+            if (kw_args) {
+                // copy in kwargs
+                memcpy(args2 + 1 + n_args, kw_args->table, 2 * n_kw * sizeof(mp_obj_t));
+            }
             new_ret = mp_call_function_n_kw(init_fn[0], n_args + 1, n_kw, args2);
             m_del(mp_obj_t, args2, 1 + n_args + 2 * n_kw);
         }
@@ -849,8 +852,13 @@ STATIC mp_obj_t instance_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value
         mp_obj_class_lookup(&lookup, self->base.type);
         meth_args = 3;
     }
-    if (member[0] == MP_OBJ_SENTINEL) {
-        return mp_obj_subscr(self->subobj[0], index, value);
+    if (member[0] == MP_OBJ_SENTINEL) { // native base subscr exists
+        mp_obj_type_t *subobj_type = mp_obj_get_type(self->subobj[0]);
+        // return mp_obj_subscr(self->subobj[0], index, value, instance);
+        mp_obj_t ret = subobj_type->subscr(self_in, index, value);
+        // May have called port specific C code. Make sure it didn't mess up the heap.
+        assert_heap_ok();
+        return ret;
     } else if (member[0] != MP_OBJ_NULL) {
         mp_obj_t args[3] = {self_in, index, value};
         // TODO probably need to call mp_convert_member_lookup, and use mp_call_method_n_kw
diff --git a/py/proto.c b/py/proto.c
new file mode 100644
index 000000000..e5053130b
--- /dev/null
+++ b/py/proto.c
@@ -0,0 +1,50 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/obj.h"
+#include "py/proto.h"
+#include "py/runtime.h"
+
+#ifndef MICROPY_UNSAFE_PROTO
+const void *mp_proto_get(uint16_t name, mp_const_obj_t obj) {
+    mp_obj_type_t *type = mp_obj_get_type(obj);
+    if (!type->protocol) return NULL;
+    uint16_t proto_name = *(const uint16_t*) type->protocol;
+    if (proto_name == name) {
+        return type->protocol;
+    }
+    return NULL;
+}
+#endif
+
+const void *mp_proto_get_or_throw(uint16_t name, mp_const_obj_t obj) {
+    const void *proto = mp_proto_get(name, obj);
+    if (proto) {
+        return proto;
+    }
+    mp_raise_TypeError_varg(translate("'%s' object does not support '%q'"),
+        mp_obj_get_type_str(obj), name);
+}
diff --git a/py/proto.h b/py/proto.h
new file mode 100644
index 000000000..2d4f80565
--- /dev/null
+++ b/py/proto.h
@@ -0,0 +1,43 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_PY_PROTO_H
+#define MICROPY_INCLUDED_PY_PROTO_H
+
+#ifdef MICROPY_UNSAFE_PROTO
+#define MP_PROTOCOL_HEAD /* NOTHING */
+#define MP_PROTO_IMPLEMENT(name) /* NOTHING */
+static inline void *mp_proto_get(uint16_t name, mp_const_obj_type_t obj) { return mp_obj_get_type(obj)->protocol; }
+#else
+#define MP_PROTOCOL_HEAD \
+    uint16_t name; // The name of this protocol, a qstr
+#define MP_PROTO_IMPLEMENT(n) .name = n,
+const void *mp_proto_get(uint16_t name, mp_const_obj_t obj);
+const void *mp_proto_get_or_throw(uint16_t name, mp_const_obj_t obj);
+#endif
+
+#endif
+
diff --git a/py/py.mk b/py/py.mk
index 17cb79264..a73b47f37 100644
--- a/py/py.mk
+++ b/py/py.mk
@@ -214,6 +214,7 @@ PY_CORE_O_BASENAME = $(addprefix py/,\
 	objtype.o \
 	objzip.o \
 	opmethods.o \
+	proto.o \
 	reload.o \
 	sequence.o \
 	stream.o \
@@ -303,12 +304,12 @@ FORCE:
 
 $(HEADER_BUILD)/mpversion.h: FORCE | $(HEADER_BUILD)
 	$(STEPECHO) "GEN $@"
-	$(Q)$(PYTHON) $(PY_SRC)/makeversionhdr.py $@
+	$(Q)$(PYTHON3) $(PY_SRC)/makeversionhdr.py $@
 
 # build a list of registered modules for py/objmodule.c.
 $(HEADER_BUILD)/moduledefs.h: $(SRC_QSTR) $(QSTR_GLOBAL_DEPENDENCIES) | $(HEADER_BUILD)/mpversion.h
-	@$(ECHO) "GEN $@"
-	$(Q)$(PYTHON) $(PY_SRC)/makemoduledefs.py --vpath="., $(TOP), $(USER_C_MODULES)" $(SRC_QSTR) > $@
+	@$(STEPECHO) "GEN $@"
+	$(Q)$(PYTHON3) $(PY_SRC)/makemoduledefs.py --vpath="., $(TOP), $(USER_C_MODULES)" $(SRC_QSTR) > $@
 
 SRC_QSTR += $(HEADER_BUILD)/moduledefs.h
 
@@ -316,7 +317,7 @@ SRC_QSTR += $(HEADER_BUILD)/moduledefs.h
 # overall config, so they need to be caught
 MPCONFIGPORT_MK = $(wildcard mpconfigport.mk)
 
-$(HEADER_BUILD)/$(TRANSLATION).mo: $(TOP)/locale/$(TRANSLATION).po
+$(HEADER_BUILD)/$(TRANSLATION).mo: $(TOP)/locale/$(TRANSLATION).po | $(HEADER_BUILD)
 	$(Q)msgfmt -o $@ $^
 
 $(HEADER_BUILD)/qstrdefs.preprocessed.h: $(PY_QSTR_DEFS) $(QSTR_DEFS) $(QSTR_DEFS_COLLECTED) mpconfigport.h $(MPCONFIGPORT_MK) $(PY_SRC)/mpconfig.h | $(HEADER_BUILD)
diff --git a/py/ringbuf.h b/py/ringbuf.h
index 5f82cc096..7fc35d266 100644
--- a/py/ringbuf.h
+++ b/py/ringbuf.h
@@ -99,4 +99,11 @@ static inline void ringbuf_put_n(ringbuf_t* r, uint8_t* buf, uint8_t bufsize)
         }
     }
 }
+
+static inline void ringbuf_get_n(ringbuf_t* r, uint8_t* buf, uint8_t bufsize)
+{
+    for(uint8_t i=0; i < bufsize; i++) {
+        buf[i] = ringbuf_get(r);
+    }
+}
 #endif // MICROPY_INCLUDED_PY_RINGBUF_H
diff --git a/py/runtime.c b/py/runtime.c
index 9968f26e0..a786619bf 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -31,8 +31,6 @@
 
 #include "extmod/vfs.h"
 
-// #include "py/mpstate.h"
-// #include "py/nlr.h"
 #include "py/parsenum.h"
 #include "py/compile.h"
 #include "py/objstr.h"
diff --git a/py/showbc.c b/py/showbc.c
index 3deb18cd3..e71d8a253 100644
--- a/py/showbc.c
+++ b/py/showbc.c
@@ -185,7 +185,7 @@ const byte *mp_bytecode_print_str(const byte *ip) {
                 num--;
             }
             do {
-                num = (num << 7) | (*ip & 0x7f);
+                num = (num * 128) | (*ip & 0x7f);
             } while ((*ip++ & 0x80) != 0);
             printf("LOAD_CONST_SMALL_INT " INT_FMT, num);
             break;
diff --git a/py/stream.c b/py/stream.c
index 08c749cc3..2ff2b76a6 100644
--- a/py/stream.c
+++ b/py/stream.c
@@ -86,8 +86,7 @@ mp_uint_t mp_stream_rw(mp_obj_t stream, void *buf_, mp_uint_t size, int *errcode
 }
 
 const mp_stream_p_t *mp_get_stream_raise(mp_obj_t self_in, int flags) {
-    mp_obj_type_t *type = mp_obj_get_type(self_in);
-    const mp_stream_p_t *stream_p = type->protocol;
+    const mp_stream_p_t *stream_p = mp_proto_get(MP_QSTR_protocol_stream, self_in);
     if (stream_p == NULL
         || ((flags & MP_STREAM_OP_READ) && stream_p->read == NULL)
         || ((flags & MP_STREAM_OP_WRITE) && stream_p->write == NULL)
@@ -341,6 +340,9 @@ STATIC mp_obj_t stream_readall(mp_obj_t self_in) {
             p = vstr_extend(&vstr, DEFAULT_BUFFER_SIZE);
             current_read = DEFAULT_BUFFER_SIZE;
         }
+        #ifdef RUN_BACKGROUND_TASKS
+        RUN_BACKGROUND_TASKS;
+        #endif
     }
 
     vstr.len = total_size;
@@ -519,7 +521,7 @@ int mp_stream_errno;
 
 ssize_t mp_stream_posix_write(mp_obj_t stream, const void *buf, size_t len) {
     mp_obj_base_t* o = (mp_obj_base_t*)MP_OBJ_TO_PTR(stream);
-    const mp_stream_p_t *stream_p = o->type->protocol;
+    const mp_stream_p_t *stream_p = mp_get_stream(o);
     mp_uint_t out_sz = stream_p->write(stream, buf, len, &mp_stream_errno);
     if (out_sz == MP_STREAM_ERROR) {
         return -1;
@@ -530,7 +532,7 @@ ssize_t mp_stream_posix_write(mp_obj_t stream, const void *buf, size_t len) {
 
 ssize_t mp_stream_posix_read(mp_obj_t stream, void *buf, size_t len) {
     mp_obj_base_t* o = (mp_obj_base_t*)MP_OBJ_TO_PTR(stream);
-    const mp_stream_p_t *stream_p = o->type->protocol;
+    const mp_stream_p_t *stream_p = mp_get_stream(o);
     mp_uint_t out_sz = stream_p->read(stream, buf, len, &mp_stream_errno);
     if (out_sz == MP_STREAM_ERROR) {
         return -1;
@@ -541,7 +543,7 @@ ssize_t mp_stream_posix_read(mp_obj_t stream, void *buf, size_t len) {
 
 off_t mp_stream_posix_lseek(mp_obj_t stream, off_t offset, int whence) {
     const mp_obj_base_t* o = (mp_obj_base_t*)MP_OBJ_TO_PTR(stream);
-    const mp_stream_p_t *stream_p = o->type->protocol;
+    const mp_stream_p_t *stream_p = mp_get_stream(o);
     struct mp_stream_seek_t seek_s;
     seek_s.offset = offset;
     seek_s.whence = whence;
@@ -554,7 +556,7 @@ off_t mp_stream_posix_lseek(mp_obj_t stream, off_t offset, int whence) {
 
 int mp_stream_posix_fsync(mp_obj_t stream) {
     mp_obj_base_t* o = (mp_obj_base_t*)MP_OBJ_TO_PTR(stream);
-    const mp_stream_p_t *stream_p = o->type->protocol;
+    const mp_stream_p_t *stream_p = mp_get_stream(o);
     mp_uint_t res = stream_p->ioctl(stream, MP_STREAM_FLUSH, 0, &mp_stream_errno);
     if (res == MP_STREAM_ERROR) {
         return -1;
diff --git a/py/stream.h b/py/stream.h
index 03e24c746..543fe8c82 100644
--- a/py/stream.h
+++ b/py/stream.h
@@ -27,6 +27,7 @@
 #define MICROPY_INCLUDED_PY_STREAM_H
 
 #include "py/obj.h"
+#include "py/proto.h"
 #include "py/mperrno.h"
 
 #define MP_STREAM_ERROR ((mp_uint_t)-1)
@@ -64,6 +65,7 @@ struct mp_stream_seek_t {
 
 // Stream protocol
 typedef struct _mp_stream_p_t {
+    MP_PROTOCOL_HEAD
     // On error, functions should return MP_STREAM_ERROR and fill in *errcode (values
     // are implementation-dependent, but will be exposed to user, e.g. via exception).
     mp_uint_t (*read)(mp_obj_t obj, void *buf, mp_uint_t size, int *errcode);
@@ -93,7 +95,7 @@ MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_ioctl_obj);
 
 // Object is assumed to have a non-NULL stream protocol with valid r/w/ioctl methods
 static inline const mp_stream_p_t *mp_get_stream(mp_const_obj_t self) {
-    return (const mp_stream_p_t*)((const mp_obj_base_t*)MP_OBJ_TO_PTR(self))->type->protocol;
+    return mp_proto_get(MP_QSTR_protocol_stream, self); 
 }
 
 const mp_stream_p_t *mp_get_stream_raise(mp_obj_t self_in, int flags);
diff --git a/py/vm.c b/py/vm.c
index b5f53ee9a..353fc8810 100644
--- a/py/vm.c
+++ b/py/vm.c
@@ -758,7 +758,7 @@ unwind_jump:;
                     } else {
                         PUSH(value); // push the next iteration value
                     }
-                    DISPATCH();
+                    DISPATCH_WITH_PEND_EXC_CHECK();
                 }
 
                 // matched against: SETUP_EXCEPT, SETUP_FINALLY, SETUP_WITH
diff --git a/py/vstr.c b/py/vstr.c
index 869b27805..91cd7f584 100644
--- a/py/vstr.c
+++ b/py/vstr.c
@@ -50,6 +50,9 @@ void vstr_init(vstr_t *vstr, size_t alloc) {
 // Init the vstr so it allocs exactly enough ram to hold a null-terminated
 // string of the given length, and set the length.
 void vstr_init_len(vstr_t *vstr, size_t len) {
+    if(len == SIZE_MAX) {
+        m_malloc_fail(len);
+    }
     vstr_init(vstr, len + 1);
     vstr->len = len;
 }