Hellcat, the PSP developer that is known for his Recovery flasher application, has begun working on an update to support the latest firmwares. Recovery Flasher is able to install different firmwares regardless of the one that’s currently installed on your PSP. On top of that, it works from the recovery menu of custom firmwares and the service menu of Pandora.
Rolling off a petition started on Wololo’s /talk last month, Hellcat has posted a video of the WIP installing 6.60 PRO B-10 to a Slim running 3.71 M33. He mentions that firmware packs will be provided for several custom firmwares including those for the 6.39 and 6.60 lineup.
No timeframe has been given for release.