diff --git a/extmod/modonewire.c b/extmod/modonewire.c
index f440f75a82..dbd519776e 100644
--- a/extmod/modonewire.c
+++ b/extmod/modonewire.c
@@ -38,9 +38,9 @@
 #define TIMING_RESET1 (480)
 #define TIMING_RESET2 (70)
 #define TIMING_RESET3 (410)
-#define TIMING_READ1 (5)
-#define TIMING_READ2 (5)
-#define TIMING_READ3 (40)
+#define TIMING_READ1  (6)
+#define TIMING_READ2  (9)
+#define TIMING_READ3  (55)
 #define TIMING_WRITE1 (10)
 #define TIMING_WRITE2 (50)
 #define TIMING_WRITE3 (10)