Turns out there were 3 variants of video boards -- ABS K7071 (text only), ABG K7072 (dumb framebuffer) and ABG K7075 (7220-based). The latter two are driven by KGS K7070 (terminal emulator with downloadable software).
K7072 wip:
WIP -- KES is a clone of iSBC-215 storage controller, but it's different internally (Z80 + Z80DMA + Z80CTC instead of 8089) and will need new code: