I've just set this up on a couple of old Cubox 1's running Arch Linux. If you could add onto the README.md that Arch uses systemd/Timers by default but installing a cronie as a package 'pacman -S cronie' followed by 'systemctl enable cronie', adds cron timers. All works fine.
Thanks for the useful utility.

I didn't have udisksctl resulting in the error shown below running efe. The error message should at least be a little more useful. Probably need to document that udisksctl is required as well. If I get time I'll submit a PR. Thanks!

efe -sdcard /dev/mmcblk1 -wifi-ssid "myssid" -wifi-pass "mypass" -email "myemail" -board "raspberrypi"       
- Reusing Raspbian Jessie Lite image /home