I had this about a year ago, ended up having to reflash the OS. It's worked fine since, being used daily and with most of the internal 64gb being used by games so it looks like the internal nand is ok. I keep all my roms on external storage and savestates are usually in the same folder so it wasn't much of an inconvenience.
GPD Win, GPD XD 64gb, Pap KIII-Plus, RS-97, RS-90, New Bittboy, 3DS XL, DSi XL, GBA SP, GBBC Clone, Gameboy Pocket, PSP Go,
HP Envy M6, Acer 522, Dell Mini 9
Psion 5 & 5MX
Tons of other old laptops and tablets.....