So lately I've been noticing that I kinda need to get with the times. I need to upgrade my psp. I'm running 3.40 OE right now and I totally missed the wagon to 3.51 m33 because I wasn't sure if it was a DA fw or not. So now I see that there are a lot of users with m33 firmware and i need to upgrade myself. From what I've seen I just do the update like any normal update [4.01m33] but I read somewhere before for 3.9Xm33 that I had to be in 3.5X m33 to be able to upgrade to that. I've looked into the readme's in 4.01m33 and see nothing of the sort but I'm not ready to go and try it without confirmation. So basically I want to know what firmware do I have to be in to be able to upgrade to 4.01m33? I have a phat psp by the way so I haven't read if that makes a difference or not.