this is not really an avr problem.
I'm actually playing with this 160x128 lcd display and have problem with the address map.
It's made by purdyelectronics and use the T6963c driver, it's internally wired like 2 lcd ( 2 times 160x64).
the text display works fine with address 0x00 and 0x8000 for upper and lower half part.
Did someone used this kind of lcd.
Thank you for any information.