The 6.3X Downgrader has been updated to Version 3.5!

Changelog:

Quote:v3.5: If the 6.20 updater MD5 check fails, it will check if the update file is 6.35, allowing non 07g/09g to downgrade to 6.35, added source, removed a few debug printf's

6.39/6.38/6.35/6.31 » 6.20/6.35 Downgrader By Davee, ported to 6.38/6.39 by someone

What does it do?
Allows users who are incontent with their firmware to downgrade to 6.20 using the Sony Updater.

How do I use it?
Copy the "PSP" folder to your PSP. The downgrader is "signed" and can be launched from OFW XMB. You need to copy the 6.20 update to PSP/GAME/UPDATE/EBOOT.PBP and for PSPgo it must be the eflash it is placed on. After setup run the downgrader and follow the onscreen instructions.

If you have anything lower than an 07g place the 6.20 update in PSP/GAME/UPDATE.
If you have an 07g or an 09g, place the 6.35 update in PSP/GAME/UPDATE.

[What does it technically do?]
6.20-6.35: It uses the utility/power exploit to gain kernel access and reboots into the updater with a special PRX running. This PRX uses the pspdecrypt functionality to decrypt the updater PRX when needed. This allows the updater to boot in the newer firmwares.
6.38/6.39: It uses my http_storage exploit to gain kernel access.  Basically, http_storage has a vulnerability in it, where I can write -1 to anywhere in memory. (I'll make a post to explain it more in-depth soon)

[I'm a dev, sup?]
The source is included in the download package.

Credits
Davee - legend. Originally made 6.35/6.31 downgrader
bbtgp - legend. Continued updates to psardumper (pspdecrypt) and the signing application "prxEncrypter".
coyotebean - legend. Coninuted updates to psardumper (pspdecrypt) and large influence and research regarding cryptographics.
kgsws - legend. First application signed and method released.
Silverspring - legend. Lots and lots of info on KIRK where wee'd still be in the dark without.
Bubbletune - BTCNF injection code and bits and bobs here ;D

READ
You run the application at your OWN risk. I am not help accountable if you PSP shoots up.

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.

Download :

Download 6.3X downgrader v3.5



Download 6.20 Firmware Update
Download 6.20 Firmware Update for PSP GO


07g/09g:
Download6.35 Firmware Update
Download6.35 Firmware Update for PSP GO



PSP Module Checker SIGNED (for checking your PSP model)


Custom firmware for 6.20 and 6.35 and 6.39(PRO-B6)

source: wololo.net
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Like:)

Fixed dl-links.