i've had alot of experience downgrading psp.
i've downgraded my own a while ago, and many of my friends' PSPs
i haven't had any problems until yesterday
when i had unsuccessfully downgraded from 3.80m33 to 3.71m33
(because he didn't want the features that weren't worth losing the irShell PSP application to)

But somehow I screwed up big time because now the NAND is missing or corrupt.
when ever it's turned on the XMB waves freeze.
All it does is show the time and the battery in the corner of the screen.
The M33 Recovery Screen can be booted by pressing the Right Trigger button,
but loading any other custom firmwares or Official Firmwares will simply do the same thing (frozen XMB waves).
the icons in the center won't show up and it turns itself off shortly after.

I tried to look up information on several other forums and spent hours and hours. (used google to search them)
they all said that the NAND is unique (like a PSP's "DNA") and loading someone else's will do very little to help. instead it will make it worse for than before.

so i came to the conclusion that i could take out the motherboard and replace it.
so i need a new slim motherboard.
then i realized i could screw that up too.
so i sent an email to 2 different Repair Services.
to see which can get me a cheaper PSP Slim Motherboard (fully functional implied)
and if they could also replace it for a reasonable price.

I was simply wondering if anyone else has had a similar problem,
or if someone else knows of a slim motherboard provider,
or if there is still hope and i could do something else.

if you've read this thank you for your attention and if you can help thanks in advanced.

I had a problem like that before. I don't know if this would work but what I did was put my friends battery and his ms in my psp & it fixed the problem. I put my bat & ms back in and formated my ms and it worked. Dont know.

Voorhees 1380

no i tried that already i used my ms and my fat battery on his slim
i tried many different methods to downgrade using UPMS and DAX's Despertar del Cementerio
and after all that the only difference between the official firmware and the custom firmware on that slim psp
was that the custom would show the recovery menu and the official wouldn't other than that they both froze.
theres nothing i can do but get a new Slim motherboard.
i searched ebay but nothing so if anyone knows someone that is offering a slim motherboard for less than $100
please pm me

i guess you'd messed up dumping the nand... didn't dax warned you about that when using the despertar del cementerio??? well i guess if you have dumped the nand properly, you can rstore it... just look for someone who has tried it and maybe he can restore it after...

first of all i didn't think there was that much of a difference between slim and phat. plus i didn't bother to read it because i had done it before with ease from official firmware to custom firmware but not from custom firmware to a slightly lower custom firmware. but lets not dwell on the confusing past. and that won't work out because even if i get the nand from someone else. its someone elses UNIQUE information. i've searched around for people that have had the same problem and have tried but the UMD stopped working. and so i figure the best solution to bringing it back is to replace the bad part.

my friend doesn't have a warrenty but i bet it wouldn't help him either way cuz he opened up his psp already plus the NAND doesn't normally go corrupt out of nowhere with official firmwares.

so like i said before does anyone know of a cheap (but working) slim motherboard. the price range im looking for is 80-90 dollars.
i already have about half of that. the other half i can get soon.

I didnt really read your whole post but have you tried reflashing a new firmware as opposed to replacing the flash0 files? let me know if you need help doing that. you can reflash 3.80 M33 or 3.90 M33 since they both work with IRSHELL.
if that doesnt work it seems like the idstorage is corrupt

yea my friend's slim psp idstorage is corrupt
flashing won't help anymore
trust me i've tried.
like i said before if you know of a good deal on
a slim psp motherboard
please pm me!

Why not just send it in to Sony, make up some BS excuse, and they'll send you a new one free of charge, they don't bother to check to see if what you're saying is true.

because my friend modded his psp and peeled off the sticker.
i doubt they'd take it because that voids the warranty.