LineageOS 14.1 update: stuck in TWRP recovery

https://www.reddit.com/r/LineageOS/comments/5rarac/tried_updating_nightly_stuck_in_twrp_recovery/

• reboot to bootloader, then run "fastboot continue" on PC. phone continues to boot normally. BUT: A normal reboot goes straight into TWRP recovery again (TWRP 3.0.0.0)

official twrp crackling support thread: - - https://forum.xda-developers.com/wileyfox-swift/development/recovery-unofficial-twrp-3-0-1-0-t3350351/page5#edit70641502

• "need to update, flash this"
  • fastboot-20170119-crackling.zip from https://androidfilehost.com/?fid=529152257862696687
• "You probably have to flash a new version of fastboot first. Look at post #46 in this thread."