Launch Adrenaline and press to download the 6.61 firmware. After finishing it will automatically terminate. Relaunch Adrenaline, this time it will go into pspemu mode. Follow the instructions on screen. The PSP Custom Firmware 6.61-Pro-C2 will work on all PSP models from the original PSP to the PSP Go and even the E1000, all you need is to be running the official 6.60 or 6.61 firmware to install and use this custom firmware. Note: On the Sony released PSP firmware 6.61, some three and a half years after the last 6.60 update.

Psp Version 6.61 Fast Recovery Download

Psp 6.61 Downgrader Download

Chronoswitch Downgrader
-> Added support for Infinity
-> Added support for 11g units to 6.60
-> Added support for 6.61
-> Added support for 09g units to 6.20
[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.
[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.
6.60: Uses sceNetMPulldown to gain kernel access.
6.61: same as 6.60 (only certloader kexploit is patched in 6.61)
[I'm a dev, sup?]
Source code included in package.
Davee - legend. Originally made 6.35/6.31 downgrader
some1 - legend. 6.38/6.39/6.60 support.
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 we'd still be in the dark without.
Bubbletune - BTCNF injection code and bits and bobs here ;D
qwikrazor87 - 6.61/11g support.
You run the application at your OWN risk. I am not help accountable if you PSP fucks up.
[Open Source]
Chronoswitch is open source! Get the source here:
Follow me on twitter: @DaveeFTW