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.