Xiaomi Poco F1 (beryllium)
Build: divested-18.1-20211212-dos-beryllium
After installing divested-18.1-20211212-dos-beryllium and divested-18.1-20211212-dos-beryllium-recovery as well as deleting the avb_custom_key and flashing the DivestOS avb_custom_key avb_pkmd.bin, booting, functionality, update support and the possibility to reset to factory defaults were checked. Everything okay.
Now the last step: fastboot flashing lock. No sooner said than done. The result is an elementary Brick.
Red triangle with white exclamation mark / ! \
The system has been destroyed
Press power button to shutdown
Fastboot can still be booted, but the system rejects all flashing attempts, because - the bootloader is locked again. fastboot flashing unlock does not work.