157w ago - Update: According to several members (including jensen76, evilsperm, and sk group) when you downgrade a PS3 with the Modified 3.41 PUP (below), it currently cripples the Blu-ray player functionality. Some additional PS3 Blu-ray fix updates are outlined HERE, however, a more stable solution is still being worked on.
To quote from garyopa on one work-around: "I was able to restore one machine I had, by copying over all the files I had in the /dev_flash2 and /dev_flash3 back to the HDD, that I had saved before when it was on v3.41"
Forum member p666 also has expanded on the PS3 Blu-ray fix a bit HERE...
157w ago - Since the release of PS3 Firmware v3.55 there is no sense in keeping the master key a secret any more - it has been released, along with unencrypted payloads, and a promise to release the source-code by PS3YES for a free PSGrade PS3 downgrader.