My Latitude 5401 went to update the Thunderbolt 3 Firmware and it locked the laptop up. Had to do a hard shutdown.
Laptop on reboot did a disk repair on C: and then on reboot I noticed that my thunderbolt dock is no longer connecting.
I tried running the firmware update manually by downloading it from DELL website and that locked up laptop right away. Tried the previous version and same result.
Maybe some kind person could provide some steps to diagnose and repair this.