We have been all waiting for something like this!
PSP Developer some1 has today published its PSP OFW 6.38 Downgrader to contribute to the Genesis Competition!
The downgrader works on a original 6.38 FW (HEN or CFW is not needed to downgrade!) and you can downgrade to Firmware 6.35.
It supports all PSPs (1000, 2000, 3000 and PSP) except 07g/09g (newer = 3000).
Support for 07G and 09G will be added later by downgrading the PSPs to OFW 6.35 instead of OFW 6.20.
He updated his Downgrader:I present to you my port of Davee's 6.35/6.31 downgrader to 6.38.
This a very simple app, just put the official 6.20 updater in (ms0/ef0 accordingly)PSP/GAME/UPDATE, and run the downgrader, this will reboot into the 6.20 "update", and allow you to downgrader to 6.20. Has been tested on 1k, 2k, 3k, and Go (doesn't support 07g or 09g, although, I might add support for them to go to 6.35 instead of 6.20, sometime in the near future).
Important note: You run the application at your OWN risk. I am not held accountable if you **** up your PSP.
Another important note: After you downgrade to 6.20, you will get a BSOD (saying that your system information is corrupted), this is OK, just click circle to reset your system information and you will be back to normal.
Final important note: It *should* still support 6.35/6.31, but I haven't actually tested it. I don't see why not though, all of it is in firmware detection.
MEGAUPLOAD - The leading online storage and file delivery service(Now with support up to 09g)
Download: uploaded.to - where your files have to be uploaded to
mu: MEGAUPLOAD - The leading online storage and file delivery service
source: wololo & pspcfw.de