diff --git a/py/emitbc.c b/py/emitbc.c
index bfd378b5e5..06f63b6f6c 100644
--- a/py/emitbc.c
+++ b/py/emitbc.c
@@ -48,9 +48,11 @@
 #define DUMMY_DATA_SIZE (BYTES_FOR_INT)
 
 struct _emit_t {
-    pass_kind_t pass;
+    pass_kind_t pass : 8;
+    uint last_emit_was_return_value : 8;
+    byte dummy_data[DUMMY_DATA_SIZE];
+
     int stack_size;
-    bool last_emit_was_return_value;
 
     scope_t *scope;
 
@@ -65,7 +67,6 @@ struct _emit_t {
     uint bytecode_offset;
     uint bytecode_size;
     byte *code_base; // stores both byte code and code info
-    byte dummy_data[DUMMY_DATA_SIZE];
 };
 
 STATIC void emit_bc_rot_two(emit_t *emit);
diff --git a/py/gc.c b/py/gc.c
index b646e8cbdf..87c458f82c 100644
--- a/py/gc.c
+++ b/py/gc.c
@@ -113,7 +113,7 @@ STATIC machine_uint_t gc_lock_depth;
 void gc_init(void *start, void *end) {
     // align end pointer on block boundary
     end = (void*)((machine_uint_t)end & (~(BYTES_PER_BLOCK - 1)));
-    DEBUG_printf("Initializing GC heap: %p..%p = %ld bytes\n", start, end, end - start);
+    DEBUG_printf("Initializing GC heap: %p..%p = " UINT_FMT " bytes\n", start, end, end - start);
 
     // calculate parameters for GC (T=total, A=alloc table, F=finaliser table, P=pool; all in bytes):
     // T = A + F + P