Downgrade Official Firmware 3.73 to 3.60

[cyberguy007]

:confused: Hi, I am from Singapore. Recently bought my PSP Slim and found that the Official Firmware is 3.73. As a result, I am unable to downgrade to the CFM 3.71-M33. May I ask is there any methods to do the Downgrade without using the Pandora-battery and memory stick? Will very much like to install ISO/CSO games on my PSP. Thanks for the help!

[NoQuarter]

ISO/CSO discussion is against the rules even if they're your backups.
You need pandora's battery,I believe the last public exploit was the lumines one and that only worked up to 3.5.

[$money_in_Da_bank$09]

is there any way you downgrade a psp slim from 5.00 m33 back to 3.60 m33? or is there a way you can downgrade a psp slime from 3.90 m33 back to 3.60 m33? anyone know? please help!!