Update: CodeTwink has confirmed that PS3 Firmware update version 3.55 blocked access to lv2 kernel "execute" access, however, if you can patch back in a method to lv1_write_htab_entry, you can re-enable this area.
Currently it is possible for PS Downgrade / JailBreak users to exit the PS3 Factory/Service Mode and get back to a normal Retail PS3 console using the lv2diag.self file_2.
Finally, although not recommended for PS3 homebrew fans, PS3 Firmware 3.55 is a mandatory update for those seeking to use PSN.
While some have reported the various bypass methods are temporarily working, more promising solutions include PS3 hackers continuing work on decrypting PS3 Firmware 3.50 with version 3.55 next in their sights.
I may wait for a bit to update my 3.50 ps3 to 3.55 until I find out more about what it blocks. But I'll be getting a 2nd ps3 in Christmas that I will keep on 3.41 and offline for as long as I own it.
The comments on the ps blog make me laugh. Idiots saying stupid things like "thank you $ony for protecting my ps3", and saying how "hackers" are bad. I'm going to laugh my a$$ off when $ony's "minor security" update bricks everyone's system or screws up other stuff. I believe $ony is going to get sloppy with the coding so they can rush these security updates out as new breakthroughs come out in the jailbreak scene.