Sony released a new firmware upgrade version 3.21 for PS3 (PlayStation 3), which famous for its “features downgrade” by removing the OtherOS ability to install another operating system on the PS3 Fat version. The removal of Other OS feature is claimed by Sony to prevent potential security threat, which many interprets as the preventive steps to avoid PS3 been hacked to run unauthorized, copied or pirated games.

GeoHot, who is famous for successfully hacking the iPhone, has tried to hack Sony PS3 for a while, successful to a minor extent only as it’s not possible yet to make general public release. GeoHot has actually advised the PS3 Fat version owners who are using or planning to use the Other OS feature to refrain from updating to new firmware version 3.21, while waiting for his hack which allows updating to 3.21 system software without losing the Other OS support.

And, finally, GeoHot is posting a video demonstrating a custom firmware (CFW) which serves as a workaround to upgrade install system firmware v3.21 with OtherOS feature intact. According to GeoHot, the custom firmware can be installed without having to open up the PS3, instead, it can be installed by restoring a custom generated PUP file, but only from PS3 firmware version 3.15 or earlier. GeoHot also lauds that possibility of the custom firmware to work on PS3 Slim to hack enable the Other OS in PS3 Slim.

Unfortunately, there is no release yet for the hacked custom firmware 3.21 with Other OS support enabled. PS3 owners decided not to upgrade and stay on firmware 3.15 can use the PS3 proxy hack to play PSN online.