Originally Posted by alexsius
Yes but my "why" means "how can ps3 recognize the cfw". What I want to understand is ,if somebody know it, how ps3 finds it is or not an upgrading ofw.
In FWs 3.56 and up the new system updater does some extra checks (that we do not yet understand) to verify the integrity of the pup. So by changing the pup in anyway, the ps3 will detect tampering and refuse to install it.