Ok I just played around with the downgrade . I wanted to test the extra HD method . I removed my 3.50 HD with all my saves and so forth and replaced with a HD I had from a 20 gig PS3 . You have to format and install 3.50 on it if by a method of USB stick (PS3 folder - UPDATE folder - 3.50 PUP ) . It will ask you to hold start and select till it starts . After you have this HD on 3.50 you use the PS3Break downgrade like their guide states . I then JB that to test , everything worked fine . After that I took out of JB mode and updated that drive back to 3.50 . I swapped HD back to my original and everything worked fine . Movie playback worked and all my data was still intact .