(adsbygoogle = window.adsbygoogle || []).push({}); If I put my PS3 on 3.56 into service mode, what features will not be available? When I get into service mode, I plan to downgrade. But only if I can install custom firmware. Thanks.

No there is no way as of now to install CFW on a 3.56 PS3 (This includes being in service mode)

That is not what I mean.

I want to go into Service Mode, DOWNGRADE to 3.55 (still in service mode I guess) and then install Kmeaw. Is this possible?

no /facepalm. youll go in service mode. be stuck on 3.56 service mode. no way of downgrading. no way of going back.