Success! For those of you having difficulty with Linux mounting your SD card, try doing a fresh format from Diskpart. Here's how:
- Open Command prompt and run "diskpart"
- select disk 1 (or whatever disk your microSD is labelled as in My Computer>Properties>Hardware>Properties>Volumes>Po pulate)
- clean
- create partition primary
- select partition 1
- active
- format fs=fat
- assign
- exit