diff --git a/extmod/modtrezormsg/modtrezormsg.c b/extmod/modtrezormsg/modtrezormsg.c
index a22a8c2e..6cd3bfe6 100644
--- a/extmod/modtrezormsg/modtrezormsg.c
+++ b/extmod/modtrezormsg/modtrezormsg.c
@@ -47,10 +47,15 @@ STATIC mp_obj_t mod_TrezorMsg_Msg_send(mp_obj_t self, mp_obj_t message) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_TrezorMsg_Msg_send_obj, mod_TrezorMsg_Msg_send);
 
-// def Msg.select(self, timeout_ms: int) -> None/tuple/bytes
-STATIC mp_obj_t mod_TrezorMsg_Msg_select(mp_obj_t self, mp_obj_t timeout_ms) {
-    int to = mp_obj_get_int(timeout_ms);
-    while (--to >= 0) {
+#define TICK_RESOLUTION 1000
+
+// def Msg.select(self, timeout_us: int) -> None/tuple/bytes
+STATIC mp_obj_t mod_TrezorMsg_Msg_select(mp_obj_t self, mp_obj_t timeout_us) {
+    int to = mp_obj_get_int(timeout_us);
+    if (to < 0) {
+        to = 0;
+    }
+    while (to >= 0) {
         uint32_t e = msg_poll_ui_event();
         if (e) {
             mp_obj_tuple_t *tuple = MP_OBJ_TO_PTR(mp_obj_new_tuple(3, NULL));
@@ -66,7 +71,8 @@ STATIC mp_obj_t mod_TrezorMsg_Msg_select(mp_obj_t self, mp_obj_t timeout_ms) {
             memcpy(vstr.buf, m, 64);
             return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
         }
-        mp_hal_delay_ms(1);
+        mp_hal_delay_us_fast(TICK_RESOLUTION);
+        to -= TICK_RESOLUTION;
     }
     return mp_const_none;
 }
diff --git a/send_udp.py b/send_udp.py
new file mode 100755
index 00000000..4b08f241
--- /dev/null
+++ b/send_udp.py
@@ -0,0 +1,9 @@
+#!/usr/bin/python
+import socket
+
+UDP_IP = '127.0.0.1'
+UDP_PORT = 21324
+MESSAGE = b'Hello, World!'
+
+sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+sock.sendto(MESSAGE, (UDP_IP, UDP_PORT))
diff --git a/src/trezor/loop.py b/src/trezor/loop.py
index 09084a3a..84286c4f 100644
--- a/src/trezor/loop.py
+++ b/src/trezor/loop.py
@@ -2,6 +2,7 @@ import utime
 import uheapq
 
 from .utils import type_gen
+from . import msg
 
 if __debug__:
     import logging
@@ -34,7 +35,10 @@ def wait(delay):
         log.debug("Sleeping for: %s", delay)
 
     last_sleep = delay
-    utime.sleep_us(delay)
+    m = msg.select(delay)
+    if m:
+        print('msg:', m)
+    return m
 
 def run_forever():
     global q, cnt
@@ -47,11 +51,12 @@ def run_forever():
             tnow = utime.ticks_us()
             delay = t - tnow
             if delay > 0:
-                wait(delay)
+                m = wait(delay)
         else:
-            wait(-1)
+            m = wait(0)
             # Assuming IO completion scheduled some tasks
             continue
+
         if callable(cb):
             ret = cb(*args)
             if __debug__ and isinstance(ret, type_gen):
diff --git a/src/trezor/msg.py b/src/trezor/msg.py
index e57b6172..f815899c 100644
--- a/src/trezor/msg.py
+++ b/src/trezor/msg.py
@@ -2,8 +2,8 @@ from TrezorMsg import Msg
 
 _msg = Msg()
 
-def select(timeout_ms):
-    return _msg.select(timeout_ms)
+def select(timeout_us):
+    return _msg.select(timeout_us)
 
 def send(msg):
     return _msg.send(msg)
diff --git a/vendor/micropython b/vendor/micropython
index da3fe60b..c4e00834 160000
--- a/vendor/micropython
+++ b/vendor/micropython
@@ -1 +1 @@
-Subproject commit da3fe60b7dc12ce393e9a63c9d6ac366b9c81045
+Subproject commit c4e00834d394bf07e3c347494648c7fe73fee50b