FAT PSP v1.5 can't update and can't go recovery...

[GEORGIAN]

Guys i got DevHooked FAT PSP v1.5 and trying to update console but i getting ERROR mesages on ANY firmware. Tryed to recover it on factory settings but nothing is hapening, RECOVERY dosn't work either-it's starting regulary.
 Then someone told me:
"You don't have a simple solution then, the problem is that the previous owner downgraded a PSP with a recent motherboard (TA-082 or newer), and the downgrade process for those motherboards partially corrupts the flash memory.
There IS a program that fixes this and makes the PSP configuration normal again, allowing it to upgrade normally at will, but the problem is, you would have to leave your PSP homebrew-ready in order to run this program"
"You only have 2 solutions: either send it to Sony, and pay them to reset the flash to their newest firmware (they'll know your warranty is void from machine behavior); or have someone install a modchip that will allow you to flash anything you like in the PSP. Will also cost you, though."

 Anyone can help me?

[Slim02]

O.k. can you run the PSP in 1.5? If so then you need to install 3.50 or 3.52 M33 CFW.. After you install one of them CFW then you want to install CFW 4.01 M33.. After CFW 4.01 M33 you then can update to any Sony OFW past 4.01 FW.. I know it works because I did this to fix the same problem on a Fat PSP with the motherboard TA-082.. Now I am running 6.20 OFW on it after being downgrade to 1.5 FW..