diff --git a/python/spi.py b/python/spi.py
index 12a9da61..6e6f5c36 100644
--- a/python/spi.py
+++ b/python/spi.py
@@ -13,7 +13,7 @@ DACK = 0x85
 NACK = 0x1F
 CHECKSUM_START = 0xAB
 
-ACK_TIMEOUT_SECONDS = 0.5
+ACK_TIMEOUT_SECONDS = 0.1
 MAX_XFER_RETRY_COUNT = 5
 
 USB_MAX_SIZE = 0x40