A quick note for other users…
I found that SD Cards formatted by Disk Utility don’t mount correctly in the TAZ. Instead, open up Terminal and type:
diskutil list
Take note of which /dev/diskX is your SD Card where X is a number.
Then type:
sudo diskutil eraseDisk FAT32 MyCardName MBRFormat /dev/diskX
Where MyCardName is your card’s name and X is the number from above.