UC1698 based LCD driven by AVR
I wouldn't trust just any display library you find on the internet to drive the display. You might be better off writing your own display library for this display controller. If you do decide to use someone else’s library you will still need to familiarize yourself with the display controller datasheet and the code you are using to make sure it is doing what it's supposed to.

Do you know what communication mode you are using between the AVR and the display? Your display controller supports seven different communication modes using a combination of the BM pins, DB15, and DB13.