hi guys, i am very new here, although not new to the scene.
i hope you can find your time for me on this forum, as others dont seem to want to help

i have flashed 50+ consoles so i am not new to this before i begin.
although i have NEVER encountered a problem, not once.
the problem (that ive only just been told about by the owner of the xbox) is that it intermitantly decides not to play originals sometimes. ok before i knew this i just assumed it was a dodgey flash on my behalf.
i am upto the latest dashboard, although i have had to downgrade the drive to stock 7485 to enable to play games (i dont know why!)
ok my question is, how on earth can i get this now to play back ups.
should i;
1) flash directly to 0251 stock
2) then re-probe the 0251 stock
3) then flash to 0251 lt 3.0
or
1) flash directly to 0251 lt 3.0 from 7485
honestly, i know this sounds newbie ish but ive never actually hit this problem before (or flashed a drive with a dodgey lazer by the sounds of it!)
i hope someone out there can help as my head has been baffled for a number of days. ive spent around 10hours on this drive and normally it only takes 15minutes!