2 files changed, 4 insertions, 3 deletions
diff --git a/lib/utils/buffer_helper.c b/lib/utils/buffer_helper.c
index f6eb8bf1e..694952e3d 100644
--- a/lib/utils/buffer_helper.c
+++ b/lib/utils/buffer_helper.c
@@ -26,10 +26,10 @@
 
 #include "lib/utils/buffer_helper.h"
 
-void normalize_buffer_bounds(int32_t* start, int32_t end, uint32_t* length) {
+void normalize_buffer_bounds(int32_t* start, int32_t end, size_t* length) {
     if (end < 0) {
         end += *length;
-    } else if (((uint32_t) end) > *length) {
+    } else if (((size_t) end) > *length) {
         end = *length;
     }
     if (*start < 0) {
diff --git a/lib/utils/buffer_helper.h b/lib/utils/buffer_helper.h
index 47042e7ef..7487b9df5 100644
--- a/lib/utils/buffer_helper.h
+++ b/lib/utils/buffer_helper.h
@@ -28,7 +28,8 @@
 #define MICROPY_INCLUDED_LIB_UTILS_BUFFER_HELPER_H
 
 #include <stdint.h>
+#include <string.h>
 
-void normalize_buffer_bounds(int32_t* start, int32_t end, uint32_t* length);
+void normalize_buffer_bounds(int32_t* start, int32_t end, size_t* length);
 
 #endif  // MICROPY_INCLUDED_LIB_UTILS_BUFFER_HELPER_H