===== Notes from inconsistencies and other troubleshooting =====
==== Ethernet flakiness ==== 

==== sdcard suddenly didn't recognize password ====
  - put original image on new sdcard. Password good
  - rebooted. password still good
  - lsblk: confirmed mmcblk1 is the 3.7GB EMMC
  - did sudo dd if=/dev/zero of=/dev/mmcblk1 bs=1M count=1
  - logged out, logged in, password worked
  - did a sudo command. Password worked.
  - rebooted. sshed in with password. Worked.
  - shutdown. Unplugged. Replugged. password worked
  - tried original sdcard again. Didn't work.