Sounds like the wrong firmware may have been flashed, there were a few different versions of the X7 over the years, with slightly different silicon inside.
I'd try flashing a different fw to the X7. Have a check on the bottom of your device for any references to the type of X7 it is,
AC8350 , B351B and B351C, EKB311B and X7 with Q7 label, B351BT
are the ones I know of, that we've stocked in the past. Over on freaktab.com there are quite a few people who spend a long time with these devices; if there isn't an external clue on your X7, you could take a photo (clear, well lit) of the circuit board inside to aid identification.