Friend bought a RROD 360 on craigslist and I fixed it for him. Fixed it... and found out the DVD Drive doesn't work. I put in 360 retail game, burned game, DVD movie, and it shows up as "Unplayable Disk."
The 360 appears to have been opened before, but I believe it was for a failed attempt at fixing the RROD because one of the X clamps were loose when flipped the mobo.
Umm maybie you could try to get the md5 of the firmware file you put in the xbox, just to be sure... There is a readme file in JF folder with the md5 hash of the files, just try to download MD5Summer and generate the hash key to be sure the file is OK.
Probably the problem could be overheat ? You should try to buy warranty stickers on ebay and send the xbox to microsoft, when it's RROD problems, it's probably a good solution... You can leave the 1.51 firmware on the drive with no problems, if the warranty sticker is on and you made no physical modifications, it should be just alright
