Hi Andrew,
Have the same problem. SD-card (32Gb sdhc) was working fine for two weeks than suddenly was not recognized anymore in android and windows (dual boot machine). I reformatted the card on a pc (fat32) and the card seems fine as I can read and write files to it on a pc-cardreader without any problems.
Reading the chuwi forums I see a lot of weird problems involving sd-cards, so the chuwi sd-cardreader has some issues…
I think it’s time for Chuwi to address these problems !
If not I will be sending my tablet back to china for a refund…
cheers