@Kazhumazu We have a 20** model, but we've been thinking of upgrading to firmware 4.88 for the new bluray keys, so we're interested too.
25**s are in this weird gray area where some can run CFW and some can't – there's a tool called MinVerChk you can get that tells you whether your PS3 is hackable or not. Even if it's not, you can still run something called HEN which enables most but not all homebrew stuff, it sounds like.