diff --git a/extmod/modonewire.c b/extmod/modonewire.c
index dbd519776e..8444181810 100644
--- a/extmod/modonewire.c
+++ b/extmod/modonewire.c
@@ -41,8 +41,8 @@
 #define TIMING_READ1  (6)
 #define TIMING_READ2  (9)
 #define TIMING_READ3  (55)
-#define TIMING_WRITE1 (10)
-#define TIMING_WRITE2 (50)
+#define TIMING_WRITE1 (6)
+#define TIMING_WRITE2 (54)
 #define TIMING_WRITE3 (10)
 
 STATIC int onewire_bus_reset(mp_hal_pin_obj_t pin) {