Originally Posted by KiwiJochen

Physically the nav is similar, because it is made by the same manufacturer.
But the boot loader in the navigation computer only loads software from a boot disc that identifies itself as Range Rover OS (LROC01S).

The boot loader cannot be changer, it is in the EEPROM of the nav computer

This is why the BMW OS, which has a bootloader of BMWC01S cannot be loaded

Therefore I repeat myself:
If it is the original Range Rover nav, it expects an OS from a Range Rover OS disc (LROC01S). It CANNOT load an OS from the BMW OS disc (BMWC01S)

DO NOT TRY

You risk corrupting the flash memory in the Range Rover nav and making the nav totally inoperable.

CONFIRM exactly what you have BEFORE you try loading an OS.

You may already have the newest Range Rover OS ever released, if that is the case no newer OS exists and the exercise is pointless.