Cannot update or downgrade 3.40 OE-A, help please?

[MyxoFish]

I recently found my old PSP 1001 and it had 3.40 OE-A on it. The original memory stick is long gone. I spent all of Sunday searching and trying to fix the problem, but nothing seems to work for me.

I'm trying to update it to 6.60.

I tried to update to 3.55 M33, placed all the appropriate files in the right location. It did not work, the PSP simply goes to a black screen after the PSP logo and then turns off.

I tried to downgrade to 1.50 from recovery, placed all the appropriate files in the right location. It did not work, the PSP simply goes to a black screen and then turns off after a while.

I created a Magic Memory Stick and then tried to create a Pandora battery. After starting the Pandora app, the PSP simply goes to a black screen after the PSP logo, and then turns off. The only app that seems to be working is Keycleaner. (I tried PSPfiler, that also did the same thing: black screen and reboot.)

Tried Hellcats as well, no dice.

Now, keep in mind, everything on the PSP is working. Everything! I tried playing Rush on UMD, worked. I tried playing Rush on ISO, it worked again. It's just not letting me update or downgrade.

[faustnero]

you need to use hellcat's recovery flasher to flash your psp firmware up to 3.71 then to 5.00 then that's when you can jump up to latest.

[MyxoFish]

you need to use hellcat's recovery flasher to flash your psp firmware up to 3.71 then to 5.00 then that's when you can jump up to latest.

Same deal, stuck at the black screen and then reboot.

(I just tried an SNES emulator, and that is working. It seems like anything that involves editing system files does not work)