If the internal flash memory (EMMC) has reached its end-of-life, it becomes "Read Only." In this state, the bootloader cannot write new data, and the phone will never boot into Android again. Final Thoughts

Ensure the BlackBerry Desktop drivers are installed on your PC so the computer recognizes the device in "Fastboot" mode.

If the device vibrates and shows the BlackBerry logo, release the buttons. Step 2: Verifying Your "Repack" or Autoloader

Blackberry Keyone Stuck In Bootloader Menu Repack Info