Reset PS3 Fat on CFW 4.80 DEX

Hi

I just bought a FAT PS3 CECHk04 which is on 4.80 Rebug DEX
It has come preloaded with alot of pkg and games that I have no use for.
I would like to completely format the ps3 as if came from factory and be able to update to 4.82.2 rebug.

How should I approch this without damaging/bricking the console.

Thanks