Does anyone have any experience of this?

Having replaced a dead Range Rover MKIII in a Range Rover P38A with one from
a BMW, I notice that several BMW specific features of the BMW MKIII
(TV, telephone, DSP, computer info, even settings such as date & time)
do not work in the Range Rover (the GPS nav does thankfully work).

Can the Range Rover OS be installed on this unit, or is it a case of
the bootloader program being hard-coded in the EEPROM to look for and
load the BMW bootloader only?

Another issue is that the spoken sat nav instructions/directions cannot
be heard (its as if the instructions are being given by the unit, but
these cannot be heard, as the speakers tone down whatever they are
playing when the sat nav seems to be giving instructions, but these are
not at all audible). Is this a result of a further incompatibility
between the BMW configured MKIII and the Range Rover, or do the
settings need to be adjusted?

The BMW configured MKIII's current OS is V18 (3-1/40), and I have the
Range Rover OS (from http://www.megaupload.com/?d=J244OCVG) as well as
V25 of the BMW MKIII OS (from
http://www.bimmerfest.com/forums/showthread.php?t=169288) and the CD
Key (from http://autos.groups.yahoo.com/group/bmwnav/files/System%
20SW/) - just need to know which OS to load now...

Many thanks,
JMNL