: OS 10.3.2 and higher include a bootloader lock that prevents downgrading to earlier OS versions (like 10.2 or 10.1) once installed.

Once OS 10.3.2 or higher is installed, you cannot downgrade to a version earlier than 10.3.2 due to security changes in the bootloader. End of Life: Legacy BlackBerry 10 services were decommissioned on January 4, 2022

Breathe New Life into Your BlackBerry Z10: A Guide to the 10.3.2 Autoloader

Blackberry Z10 10.3 2 Autoloader ^hot^ -

: OS 10.3.2 and higher include a bootloader lock that prevents downgrading to earlier OS versions (like 10.2 or 10.1) once installed.

Breathe New Life into Your BlackBerry Z10: A Guide to the 10.3.2 Autoloader : OS 10