diff --git a/py/parsenum.c b/py/parsenum.c
index c73ae54a1..0915098d6 100644
--- a/py/parsenum.c
+++ b/py/parsenum.c
@@ -81,7 +81,7 @@ mp_obj_t mp_parse_num_integer(const char *restrict str_, size_t len, int base, m
     for (; str < top; str++) {
         // get next digit as a value
         mp_uint_t dig = *str;
-        if (unichar_isdigit(dig) && dig - '0' < base) {
+        if (unichar_isdigit(dig) && (int)dig - '0' < base) {
             // 0-9 digit
             dig = dig - '0';
         } else if (base == 16) {
diff --git a/py/parsenumbase.c b/py/parsenumbase.c
index 8d057af18..73a3372f0 100644
--- a/py/parsenumbase.c
+++ b/py/parsenumbase.c
@@ -24,7 +24,9 @@
  * THE SOFTWARE.
  */
 
-#include "py/parsenum.h"
+#include "py/mpconfig.h"
+#include "py/misc.h"
+#include "py/parsenumbase.h"
 
 // find real radix base, and strip preceding '0x', '0o' and '0b'
 // puts base in *base, and returns number of bytes to skip the prefix