How to use the PS3 user cheat to downgrade PS3
We know that the PS3 user cheat has the both jailbreak and game cheat features. You don't need to buy another jailbreak item to work with CHT,PS3 userchaet only works on V3.41 PS3 system, and if your system is lower than V3.41, just update to V3.41 and then use CHT to cheat games, if you have higher V3.41 system(V220.127.116.11), you also can use PS3 user cheat do the downgrae first and then cheat games later.
How to downgrade FW3.55/3.50 to 3.41 with PS3 USer cheat?
step 1: download the downgrade file here : downgrade.rar and Extraction file "downgrade.bin",don't change the file name.
step 2: insert CHT dongle into the computer, can show that a removable disk drive.
step 3: copy downgrade.bin to the root of a removable disk drive.
step 4: Safely Remove removable disk. now this is downgrade mode. Delete the "downgrade.bin", it will recover to the common mode.
step 5: for more information, please refer to the following URL: PS3,break, PS3break,PS3 dongle, PS3break.com
Downgrade Firmware Package for V3.50 to V3.41.
Downgrade Firmware Package for V3.55 to V3.41
Source: official site