diff --git a/ports/rp2/mpconfigport.h b/ports/rp2/mpconfigport.h
index 91d0c29b3a..35d1645522 100644
--- a/ports/rp2/mpconfigport.h
+++ b/ports/rp2/mpconfigport.h
@@ -88,6 +88,7 @@
 #define MICROPY_PY_SYS_STDFILES                 (1)
 #define MICROPY_PY_SYS_STDIO_BUFFER             (1)
 #define MICROPY_PY_SYS_PLATFORM                 "rp2"
+#define MICROPY_PY_UERRNO                       (1)
 #define MICROPY_PY_THREAD                       (1)
 #define MICROPY_PY_THREAD_GIL                   (0)