From all I could find, the CPU is Allwinner H64, I think it's the only model that has this particular CPU. I don't know if another one is compatible. A64 maybe?
CPU1: Allwinner H64 (1.2 GHz, 4 cores)
https://wikidevi.wi-cat.ru/Remix_Mini
Stock bootloader: U-Boot 2014.07
Stock FW OS: Linux 3.10.87 ReMix OS 2.0
http://en.techinfodepot.shoutwiki.com/wiki/Remix_Mini
Boot log
https://gist.github.com/ssvb/bd0911652399cf1e79be
https://fcc.report/FCC-ID/2AF86-RM1G