I have decided to put Kmeaw's CFW 3.55 on my PS3 today, and I was wondering if it is possible to update the console to OFW (maybe 3.60) afterwards in order to play a new game that may not already work on CFW? I know I can't simply change back then, I'm just curious if it works one way
If I read it right, you are asking if you can update from Kmeaw CFW 3.55 to PS3 OFW 3.60? If so, the answer is yes you can always update to higher OFW but of course you will lose the ability to use homebrew/backups once you do.
The games won't, but if you take the console online via PSN Sony still may be able to tell based on the PS3's install log, etc. Most who use their previously-modified console online first use one of the PS3 cleaner apps to wipe the history and often reformat their HDD as an extra precaution. If you don't plan to go online with it simply updating it from 3.55 CFW to 3.6 OFW will let you play the 3.6 titles though.