upgrading PSP custom firmware from older version?

[ujnhunter]

I can't remember but I had CFW 3.xx and had a difficult time figuring how to get to 5.xx m33 or whatever... I had to upgrade to CFW 4.xx or something to get to 5.xx m33 because 5.xx m33 wouldn't install from the lower CFW 3.xx. Wow... I just confused myself... hope it doesn't hurt.

[Niode]

I went from 3.3 CFW (one of the last Dark Alex made CFW) straight to 5.50M33 using the 5.50M33 gen-b installer. Had no issues, it worked straight away.

[grittykitty]

i'll explain what happened - i think i have 5.00m33 (i don't have it in front of me, but that sounds right) and i want to upgrade to 5.55... it's my understanding that you have to upgrade to gen-a first, and then you can upgrade to gen-b.

i did everything i was supposed to, but the updated file shows up as a corrupted file (which of course you can't run). i tried copying the files on both windows and mac, and neither worked. any suggestions?

by the way, it's a psp-1000, the fat one. the battery is not an official sony one, if that makes any difference.

[Niode]

The only time I've gotten a corrupted file is when I use my M2 with a pro-duo adaptor, and that's only on PSP-PSX games.

Just check that you've got a non-corrupt version of the update (it should have a md5).