I've installed TWRP 3.2.3-0 (eventually) and now I've got the famous "Verification failed" problem:
Unable to restart your device. The integrity verification has failed. You need to reset your device to factory default settings. This will erase all your data. Resistance is futile.
When I press "RESET" it boots into TWRP and runs an OpenRecoveryScript (bloody quickly) and then reboots to the "Verification error" screen.
I've got a TWRP backup, and there's no data on there anyway. I'm on Linux so I've used Heimdall to flash TWRP.
Volume down+Power takes me to the "Verification failed" screen. Home+Volume down+Power does the same. Any ideas how to progress? I only want to debloat the device. TIA