This backup is useful if you ever need to reinstall the same firmware after a hard drive swap.
You should always source your firmware directly from the official PlayStation System Software page to avoid malware or corrupted files. Firmware Ps3updat.pup
Turn off the console. Then press and hold the power button until you hear two beeps (about 5-10 seconds). Release. This backup is useful if you ever need
Understanding the differences between official system updates and other software versions. Then press and hold the power button until
file specifically contains the data required to update or reinstall this system software. How to Install the Firmware
No, not on an official firmware console. The PS3 checks the version number in the PUP and rejects anything lower than the current installed version. Downgrading requires hardware flashers (E3 Flasher, Teensy++) or a CFW console.
Sony’s response on 3xxx/4xxx consoles was to: