Download KitKat 4.4.2 Stock Firmware for Allwinner A80 OptimusBoard from here or here. Here you'll find a good tutorial on how to flash it.
Archive name: sun9iw1p1_android_optimus_v1.2_20140930
Archive file size: 317 MB
Image file name: sun9iw1p1_android_optimus_v1.2_20140930.img
Device: UltraOcta A80 OptimusBoard
Support: Allwinner A80
Build number: kylin_optimus-eng 4.4.2 KVT49L 20140929 test-keys
FW Version: v1.2
Pixels: 1280x800