Hi! I have two boards that doesn't have dedicated images. So I can help with testing OMV4 for these boards. I think it is old crap, but maybe someone needs testing.
Radxa Rock 2 with RK3288 on Square board, rare board, schematics are here.
Cubieboard2 on Allwinner A20. One of first revisions with NAND. Schems are here.