diff --git a/py/emitnative.c b/py/emitnative.c
index 07b984b780..0affbeb0b2 100644
--- a/py/emitnative.c
+++ b/py/emitnative.c
@@ -2058,7 +2058,7 @@ STATIC void emit_native_unwind_jump(emit_t *emit, mp_uint_t label, mp_uint_t exc
             ASM_MOV_REG_PCREL(emit->as, REG_RET, label & ~MP_EMIT_BREAK_FROM_FOR);
             ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_HANDLER_UNWIND(emit), REG_RET);
             // Cancel any active exception (see also emit_native_pop_except_jump)
-            emit_native_mov_reg_const(emit, REG_RET, MP_F_CONST_NONE_OBJ);
+            ASM_MOV_REG_IMM(emit->as, REG_RET, (mp_uint_t)MP_OBJ_NULL);
             ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_VAL(emit), REG_RET);
             // Jump to the innermost active finally
             label = first_finally->label;
@@ -2153,9 +2153,8 @@ STATIC void emit_native_with_cleanup(emit_t *emit, mp_uint_t label) {
 
     ASM_MOV_REG_LOCAL(emit->as, REG_ARG_1, LOCAL_IDX_EXC_VAL(emit)); // get exc
 
-    // Check if exc is None and jump to non-exc handler if it is
-    emit_native_mov_reg_const(emit, REG_ARG_2, MP_F_CONST_NONE_OBJ);
-    ASM_JUMP_IF_REG_EQ(emit->as, REG_ARG_1, REG_ARG_2, *emit->label_slot + 2);
+    // Check if exc is MP_OBJ_NULL (i.e. zero) and jump to non-exc handler if it is
+    ASM_JUMP_IF_REG_ZERO(emit->as, REG_ARG_1, *emit->label_slot + 2, false);
 
     ASM_LOAD_REG_REG_OFFSET(emit->as, REG_ARG_2, REG_ARG_1, 0); // get type(exc)
     emit_post_push_reg(emit, VTYPE_PYOBJ, REG_ARG_2); // push type(exc)
@@ -2175,9 +2174,9 @@ STATIC void emit_native_with_cleanup(emit_t *emit, mp_uint_t label) {
     emit_call(emit, MP_F_OBJ_IS_TRUE);
     ASM_JUMP_IF_REG_ZERO(emit->as, REG_RET, *emit->label_slot + 1, true);
 
-    // Replace exception with None
+    // Replace exception with MP_OBJ_NULL.
     emit_native_label_assign(emit, *emit->label_slot);
-    emit_native_mov_reg_const(emit, REG_TEMP0, MP_F_CONST_NONE_OBJ);
+    ASM_MOV_REG_IMM(emit->as, REG_TEMP0, (mp_uint_t)MP_OBJ_NULL);
     ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_VAL(emit), REG_TEMP0);
 
     // end of with cleanup nlr_catch block
@@ -2255,7 +2254,7 @@ STATIC void emit_native_for_iter_end(emit_t *emit) {
 STATIC void emit_native_pop_except_jump(emit_t *emit, mp_uint_t label, bool within_exc_handler) {
     if (within_exc_handler) {
         // Cancel any active exception so subsequent handlers don't see it
-        emit_native_mov_reg_const(emit, REG_TEMP0, MP_F_CONST_NONE_OBJ);
+        ASM_MOV_REG_IMM(emit->as, REG_TEMP0, (mp_uint_t)MP_OBJ_NULL);
         ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_VAL(emit), REG_TEMP0);
     } else {
         emit_native_leave_exc_stack(emit, false);