diff --git a/firmware/PIMORONI_YUKON/mpconfigboard.h b/firmware/PIMORONI_YUKON/mpconfigboard.h
index 5f46555..68455d7 100644
--- a/firmware/PIMORONI_YUKON/mpconfigboard.h
+++ b/firmware/PIMORONI_YUKON/mpconfigboard.h
@@ -1,6 +1,6 @@
 // This is a hack! Need to replace with upstream board definition.
 #define MICROPY_HW_BOARD_NAME          "Pimoroni Yukon"
-#define MICROPY_HW_FLASH_STORAGE_BYTES (15 * 1024 * 1024)
+#define MICROPY_HW_FLASH_STORAGE_BYTES (14160 * 1024)
 
 #define MICROPY_HW_USB_VID (0x2E8A)
 #define MICROPY_HW_USB_PID (0x105B)