Same issue - 64GB MicroSDXC is only able to be used when formatted FAT32. I've tried on a Z10 and Z30 with 10.2.1.1055 and earlier on 10.2.1.476 (only on the Z10). I've seen a few leaks that specifically note support for exFAT however I do not believe it is actually supported as the driver that needs to be downloaded appears to be unavailable/uninstallable/nonfunctional.
"file:///pps/system/filesystem/properties" reports:
Code:
[n]@properties
filesystems:json:{"qnx4":{"support":"unknown"},"qnx6":{"support":"available"},"fat":{"support":"available"},"exfat":{"support":"unknown"},"ext2":{"support":"unknown"},"ntfs":{"support":"unknown"},"hfs":{"support":"unknown"},"udf":{"support":"unknown"},"rcfs":{"support":"available"}}
which I take to mean under 10.2.1.1055 exFAT support is, well, *unknown*.
Has ANYONE successfully mounted an exFAT card on a BB10 device running any OS version?