diff --git a/py/emitglue.c b/py/emitglue.c
index 5916586aea..99cd3f3832 100644
--- a/py/emitglue.c
+++ b/py/emitglue.c
@@ -107,7 +107,7 @@ void mp_emit_glue_assign_native(mp_raw_code_t *rc, mp_raw_code_kind_t kind, void
 
 #ifdef WRITE_CODE
     FILE *fp_write_code = fopen("out-code", "wb");
-    fwrite(fun_data, len, 1, fp_write_code);
+    fwrite(fun_data, fun_len, 1, fp_write_code);
     fclose(fp_write_code);
 #endif
 #endif
diff --git a/py/vm.c b/py/vm.c
index c0116bbeb9..8c59b9c3aa 100644
--- a/py/vm.c
+++ b/py/vm.c
@@ -925,33 +925,29 @@ exception_handler:
                 mp_uint_t code_info_size = code_info[0] | (code_info[1] << 8) | (code_info[2] << 16) | (code_info[3] << 24);
                 qstr source_file = code_info[4] | (code_info[5] << 8) | (code_info[6] << 16) | (code_info[7] << 24);
                 qstr block_name = code_info[8] | (code_info[9] << 8) | (code_info[10] << 16) | (code_info[11] << 24);
-                mp_uint_t source_line = 0;
                 mp_uint_t bc = code_state->ip - code_info - code_info_size;
                 //printf("find %lu %d %d\n", bc, code_info[12], code_info[13]);
-                const byte* ci = code_info + 12;
-                if (*ci) {
-                    source_line = 1;
-                    mp_uint_t c;
-                    while ((c = *ci)) {
-                        mp_uint_t b, l;
-                        if ((c & 0x80) == 0) {
-                            // 0b0LLBBBBB encoding
-                            b = c & 0x1f;
-                            l = c >> 5;
-                            ci += 1;
-                        } else {
-                            // 0b1LLLBBBB 0bLLLLLLLL encoding (l's LSB in second byte)
-                            b = c & 0xf;
-                            l = ((c << 4) & 0x700) | ci[1];
-                            ci += 2;
-                        }
-                        if (bc >= b) {
-                            bc -= b;
-                            source_line += l;
-                        } else {
-                            // found source line corresponding to bytecode offset
-                            break;
-                        }
+                mp_uint_t source_line = 1;
+                mp_uint_t c;
+                for (const byte *ci = code_info + 12; (c = *ci);) {
+                    mp_uint_t b, l;
+                    if ((c & 0x80) == 0) {
+                        // 0b0LLBBBBB encoding
+                        b = c & 0x1f;
+                        l = c >> 5;
+                        ci += 1;
+                    } else {
+                        // 0b1LLLBBBB 0bLLLLLLLL encoding (l's LSB in second byte)
+                        b = c & 0xf;
+                        l = ((c << 4) & 0x700) | ci[1];
+                        ci += 2;
+                    }
+                    if (bc >= b) {
+                        bc -= b;
+                        source_line += l;
+                    } else {
+                        // found source line corresponding to bytecode offset
+                        break;
                     }
                 }
                 mp_obj_exception_add_traceback(nlr.ret_val, source_file, source_line, block_name);