I found a video of someone having a go at fixing a Land Rover MOST system.

This video gives some easy checks you can do to prove Fibre Optic Ring.
(Note problem was a module power supply in boot-----NOT MOST Ring)

The Infotainment Control Module supplies the master clock to system be working, the rest can be bypassed.
You can shine a light down fibres to prove they work.
Actual FL2 system modules shown in workshop manual.
It appears that there are lots of MOST module/system self checks carried out, which should log Error Codes.
I cannot find anything about the MOST Addressing System, I suspect reprogramming to include the FL2's VIN is only applicable to security sensitive modules. (Has anyone the definitive answer to this?)

In answer to above question about bending fibres. The minimum bending radius is 10 times (or better 20 times) the outer cable diameter.
Think of the light as electro-magnetic waves travelling down a dielectric waveguide dependant on the refractive index presented to it by a straight line fibre/sheath interface.
Bending upsets the refraction and the radiation (light) starts to escape causing losses which suddenly increase as you go below this radius.
Great care must also be taken installing fibre optics as they can be damaged by bending.
It is true that gapping, dirt or misalignment at connections can excessively attenuate signals.



Also how to dismantle the Infotainment Consel (including the MOST connections)

 FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 77k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

Top video has answered one of my questions. Looking at the MOST diagram you need to follow the arrows not the number sequence.
FL2 dash isn’t in the MOST loop like the RR but I wonder if the hard drive is in the CD player like the RR though. It’s a big heavy unit for just a CD player and as I said earlier it does make a load of computer type noise as if it’s trying to boot up but fails. I say that but I don’t know if a good unit would make the same noise after doing a hard reset removing the metal link in the boot fuse box.
Has anyone else done or about to do a reset?
Is there anyone in West Cornwall that’d let me test their cd unit in my car? 2008 HSE td4

Followed the MOST loop as per the arrows on the diagram and all is well.
I pulled the plug on the ICM (fascia with the on/off knob and clock) and there was no light coming from the IHU (cd player) MOST lead, there was a flashing red light in the ICM unit itself and when I lined the plug up with that light source I could see the loop was made and flowing. I suppose this is normal as it appears to start from the ICM and that’s why you chase the light from it : 1,7,6,5,4,3,2,1


 2008 HSE td4

IanMetro wrote:

I cannot find anything about the MOST Addressing System, I suspect reprogramming to include the FL2's VIN is only applicable to security sensitive modules. (Has anyone the definitive answer to this?)

I think I am just going to have to buy a couple of units, I was hoping someone local would lend me them.
Today I spoke to the mechanic who changed the ecu for the PO, he told me he thought it had received a voltage spike.
I read in the archives that Land Rover warned the navigation computer is particularly susceptible to voltage spikes so I think that’s probably where I’ll start followed by the integrated head unit (CD player). Maybe a newer bluetooth module first as I would be buying one anyway, not sure yet.
I think it’s probably cheaper to buy the modules than pay a tech to diagnose. 2008 HSE td4

How are you getting on with your problem?

Apparently, because the p.o. had to have another dash unit fitted it couldn’t be linked to the stereo and parking sensors at an indy, think they had enough trouble getting a 2nd hand dash to work full stop. Land Rover dealer “might” be able to do it but would probably require a brand new dash which I ain’t paying for. Cars too old, it’s just a runabout really. 2008 HSE td4

I wouldn't consider a 2008 HSE potentially worth a reasonable amount of money too old to be made to work correctly, or maybe I'm in the wrong job. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.