I don't understand why everybody are trying to make custom Firmware out of 3.55 since 3.55 seems to be a 3.50 with fewer security holes. Wouldn't it be easyer to to make a custom out of 3.50 and spoof it to 3.55?. For downgrading isn't just to make a pup out of the 3.50 pup that the PS3 accepts? with all the signing tools this should be quite easy you just sign the 3.50 pup that you spoofed with 3.55 Keys.
I am just thinking out loud but it seems like the shorter way to go I bet that you couold log into PSN with a spoofed 3.50. 3.41 and 3.50 are really different so The PSN server has real easy to recognize 3.41. Howeever 3.55 is rushed because of the recent downgrading so they didn't really put anything new into it beside the security updates, and it's the security updates we don't want,
I am sure 3.55 is modified 3.50 code, if sony could modify it why shouldn't our dear hackers be able to? Somebody who is used to this should take a look at the lines of code and se what is different and change everything that isn't security related, then name the 3.50 code 3.55 and try to upgrade.
I am not a coder but it seems 3.55 is just a patched 3.50, since PSN worked after Geohots patch it should still work with a miner change to the 3.50 code....