[Psycogeek]

i would just be guessing, because you didnt indicate if this is moving lines, or stays that way.
a display like this without any cracking , could indicate that the ribbon connector thing that connects the display is loose.
This looks a bit more like a hardware issue than a software issue. but certannly if you had proper firmware on the device, then damaged the device, and it got like this, it is unlikly that some sort of upgrade of the firmware itself would resolve the issue.
If you had done an upgrade OF the firmware and suddenly got an issue like this,that would be different.
the player still being operational, would indicate (almost certannly) that the software is still working fine, it is only a display issue, which is probably not going to be addressed with software.

what do you have to lose? open it up and check the lcd itself for damage, if the lcd is still intact, then check any connections that are adjustable and re-solidify them.