diff --git a/USB-protocol.md b/USB-protocol.md
index 9d8b6ac..7b0df4a 100644
--- a/USB-protocol.md
+++ b/USB-protocol.md
@@ -98,7 +98,7 @@ Commands are typically a one-byte command ID, followed by a variable amount of d
 ### Bootloader mode
 
 * **`0xf1`: Send unlock/authentication code**
-  * Arguments: 3 bytes from [FT240X EEPROM](FT240X-EEPROM) word locations `0x12:0x13`, followed by a *fixed* 23 zero bytes
+  * Arguments: 3 bytes from [FT240X EEPROM](FT240X-EEPROM) word locations `0x12:0x13` (little-endian, so low byte of 0x12 first, then hi byte of 0x12, then lo byte of 0x13), followed by a *fixed* 23 zero bytes
   * No response
 * **`0x90`: Spartan-3AN internal SPI flash chip select**
   * Arguments: *fixed* `0x00`