Downgrading your Playstation 3 firmware to the 3.55 version is an essential part of the console "jailbreaking" process. However, it comes at the user's own risk. You are in danger of voiding your console warranty and can even be barred from the Playstation Network for violating Sony's terms of service. Many people choose to downgrade their PS3 consoles back to the 3.55 firmware update because a lot of jailbreak programs and emulators are not compatible with the most recent PS3 updates.
Download the PS3 Downgrade Tool from the Carreira House website onto your desktop computer (see Resources).
Insert the USB flash drive into your desktop and create a folder on the device called "LVLDIAG." Inside this folder, place the two files "lvl1.mp3" and "lvl2diag.PSS" from the downloaded files in step 1.
Create another folder named "UPDATE" and place the "PS3 FIRMWARE" file inside and then disconnect your USB device.
Plug the USB flash drive into the second USB port on your console. Power up your PS3. Go to "Music" and select "Display all."
Select the "lvl1.mp3" file and allow 10-15 minutes for the file to restore the PS3 BIOS to 3.55.
Downgrading your console can cause it to become unstable and potentially damage your system.