Hi, i bought my psp back in 2004(?) in hong kong. (i dont live in hong kong) so atm, i am currently trying to play Black Rock Shooter the game.
However it freezes on cinematics. therefore i assumed its a fireware problem plus that im interested in updating. the problem occured on 5.50Pro4. i currently flashed my self back to 5.50Gen-D(full). i still have the 5.50Pro4 files if i should upgrade back to that.
i have little to none experience in PSP hacking/CFW areas. i bought my psp preloaded with CFW, which i flashed my self to 5.50 with no apparent problem. i am not in possession of a pandora battery or MMS nor do i know how to make one (not prepared to invest in one, since i only picked up my psp again to try the BRS game)
SO to the main point, I hope to upgrade to a 6.xx CFW, but i cant upgrade to any 5.50+ OFW because i get a DRNFFFFFFD7 error. i already used the Keycleaner and it didnt work. if anyone can provide any direction, i would be ever so grateful.

My current Stats are:
5.50GEN-D (Full)
TA086 Motherboard
FAT1006 (01g)
FatV4
according to PSPIdent -
CFW: Yes, w/custom IPL

PLease, if anyone can help me on this, please do. If anyone know how to fix the BRS game it self, that would be also extremely helpful.
Thank you for your time and thank you in advance. i will try to reply asap.