I have a similar issue. The tablet refuses to accept my Samsung 64GB Class I SDXC card.
Plopped in an old Strontium 32GB Class 10 SDHC card and it detects it in less than a second.
No problems reading either cards on my PC.
Could this just be a simple driver issue?
My Hi10 actually detects the 64GB card as SD storage, but just doesn’t recognize it as an actual storage volume.