diff --git a/ports/unix/mphalport.h b/ports/unix/mphalport.h
index 95ad63221..89d23ca5d 100644
--- a/ports/unix/mphalport.h
+++ b/ports/unix/mphalport.h
@@ -64,11 +64,6 @@ static inline int mp_hal_readline(vstr_t *vstr, const char *p) {
 
 #endif
 
-// TODO: POSIX et al. define usleep() as guaranteedly capable only of 1s sleep:
-// "The useconds argument shall be less than one million."
-static inline void mp_hal_delay_ms(mp_uint_t ms) {
-    usleep((ms) * 1000);
-}
 static inline void mp_hal_delay_us(mp_uint_t us) {
     usleep(us);
 }
diff --git a/ports/unix/unix_mphal.c b/ports/unix/unix_mphal.c
index 3fe2fa9fe..28a4ca2c4 100644
--- a/ports/unix/unix_mphal.c
+++ b/ports/unix/unix_mphal.c
@@ -220,3 +220,17 @@ uint64_t mp_hal_time_ns(void) {
     gettimeofday(&tv, NULL);
     return (uint64_t)tv.tv_sec * 1000000000ULL + (uint64_t)tv.tv_usec * 1000ULL;
 }
+
+void mp_hal_delay_ms(mp_uint_t ms) {
+    #ifdef MICROPY_EVENT_POLL_HOOK
+    mp_uint_t start = mp_hal_ticks_ms();
+    while (mp_hal_ticks_ms() - start < ms) {
+        // MICROPY_EVENT_POLL_HOOK does mp_hal_delay_us(500) (i.e. usleep(500)).
+        MICROPY_EVENT_POLL_HOOK
+    }
+    #else
+    // TODO: POSIX et al. define usleep() as guaranteedly capable only of 1s sleep:
+    // "The useconds argument shall be less than one million."
+    usleep(ms * 1000);
+    #endif
+}
diff --git a/ports/windows/windows_mphal.c b/ports/windows/windows_mphal.c
index b442b5914..49daa0542 100644
--- a/ports/windows/windows_mphal.c
+++ b/ports/windows/windows_mphal.c
@@ -261,3 +261,9 @@ uint64_t mp_hal_time_ns(void) {
     gettimeofday(&tv, NULL);
     return (uint64_t)tv.tv_sec * 1000000000ULL + (uint64_t)tv.tv_usec * 1000ULL;
 }
+
+// TODO: POSIX et al. define usleep() as guaranteedly capable only of 1s sleep:
+// "The useconds argument shall be less than one million."
+void mp_hal_delay_ms(mp_uint_t ms) {
+    usleep((ms) * 1000);
+}