diff --git a/ports/rp2/mpthreadport.h b/ports/rp2/mpthreadport.h
index 4583f6f53..5eb0bff39 100644
--- a/ports/rp2/mpthreadport.h
+++ b/ports/rp2/mpthreadport.h
@@ -41,7 +41,7 @@ static inline void mp_thread_set_state(struct _mp_state_thread_t *state) {
 }
 
 static inline struct _mp_state_thread_t *mp_thread_get_state(void) {
-    return core_state[get_core_num()];
+    return (struct _mp_state_thread_t *)core_state[get_core_num()];
 }
 
 static inline void mp_thread_mutex_init(mp_thread_mutex_t *m) {