This page is obsolete. Please head to: for information on the latest hack of 400d.[]

This page contains information that is eventually meant to result in a CHDK port for the 400D / Rebel XTi.

Firmware info[]


Latest Version v1.1.1
Firmware can be updated by end user and downloaded from Canon website.
Firmware can be decrypted with the same utility that works for the Canon 30D.,134.msg2461.html#msg2461
firmware is loaded at 0xFF810000

Firmware content[]

Fir_tool 0.5 for 5D/30D/400D (9May2010)

fileLen = 0x4aad50
---.fir header---
0x000: modelId = 0x80000236, (400D / Rebel XTi, VxWorks)
0x010: version = 1.1.0
---ciphered part (xor)---
xor_decoding [0x20-0x4aad50]... OK (0236_110_firmware.bin)
0x020: checksum = 0xe365a664
checksum computing [0x0-0x4aad50] is OK!
0x024: updater offset = 0x30
0x028: firmware pack offset = 0x127c90
0x02c: = 0x0
0x030: ---updater---
0x127c90: ---firmware---
0x127c90: (+0x000) firmware checksum = 0xea620eaa
checksum computing [0x127c94-0x4aad50] is OK!
0x127c94: number of files in the pack = 13
0x127c98: offset to the file table = 0x18 (from 0x127c90)
0x127c9c: header size = 0x220 (from 0x127c90). end of header = 0x127eb0
0x127ca0: size of file table = 0x208
0x127ca4: size after table = 0x382ea0
0x127c88: (+0x018) files table
0x127ca8: 0x0008 0x000220 0x01b040 BIND_RESOURCE
0x127cd0: 0x0003 0x01b260 0x3594f0 MAIN_FIRMWARE
0x127cf8: 0x0004 0x374750 0x000004 ModelID
0x127d20: 0x0004 0x374754 0x000005 FirmwareVersion
0x127d48: 0x0004 0x374759 0x00000a ICUVersion
0x127d70: 0x0004 0x374763 0x0001f8 FileSizeTable
0x127d98: 0x0004 0x37495b 0x001aff LensNameTbl
0x127dc0: 0x0004 0x37645a 0x000094 LensPOTbl
0x127de8: 0x0004 0x3764ee 0x000f2c AdjWbFix
0x127e10: 0x0004 0x37741a 0x00469a CrwParam
0x127e38: 0x0004 0x37bab4 0x00722c FlavorLutParam
0x127e60: 0x0004 0x382ce0 0x000218 ColorAdjustDefaultAngel
0x127e88: 0x000b 0x382ef8 0x0001c8 EEP
0x127eb0: (+0x220) end of table, first file

Hardware info[]

DIGIC II, ARM946ES VxWorks 5.5.1 EOS 400D already provides many of the CHDK features.

Firmware Hack Info[]

A hacked firmware is developed (in the forum) :,3290.0.html


400plus project on Google Code


Please use updated information here:


Please refer to the guide at:


(Apologies for mistakes)

Big thanks goes to:
for the initial work: Owerlord, Seklth, Thaibv & Foldesa from CHDK Forum
for the current project: EduPerez, Sergei, 0xAF
Installation : raingrove, thaibv, 0xAF