I fixed it!!! It's possible!!!
It was last week that I actually was able to work on the car as it's parked in storage at the moment. So here is a very basic DIY, as always use at own risk. Just because it worked for me doesn't mean it will work for you. </disclaimer.>
Tools required:
- R270+ CAS4 Eeprom reader (AliExpress)
- Hot air soldering station (AliExpress)
- A couple of 080DOWQ eeprom chips.
- BMW Scanner 1.4 (software and drivers are easy to find. Use on Windows XP is my advice) get the cable from China, it's dirt cheap.
- INPA (software can be found online) get the cable from a proper source so you know that the cable is good.
- NCS Expert (I used Revtors Profile) freely available online and if you buy a INPA cable there are some companies that includes a Entire BMW package with many tools.
Step one. Buy a second hand unit from Ebay. (especially the German one they are a lot cheaper then the Dutch version and will send any parts your way.) Check with realoem that the part number matches your VIN.
Step two. Lower down your steering wheel and pull it forward as far is it will go. Remove the screw in the top of the cluster it's a Torx 20 if I am not mistaken. Pull your old cluster forward carefully, as soon as it can tilt, slowly tilt so you can reach the back and unplug the cable. you need to push a clip down and then the release is free to move. Put you original cluster somewhere safe and out of harms way. In my case the trunk is a good as place as any.
Step three. Connect the new cluster to you car. You need to make sure that you know the VIN number of your replacement cluster. Don't worry about any errors being thrown your way. We will remove these later in the process. Boot up the laptop and use BMW Scanner to scan your car, it's going to give you an error about VIN not matching. This is a good thing, it means you will have the incorrect VIN number. Write the incorrect VIN number down. This is also the part where you have the opportunity to check if your new cluster is any good and functioning correctly. (especially the LED lights)
Step four. Dismantle the new cluster, about the first 5 min of the video in link.
https://www.youtube.com/watch?v=lbj2tSZvzI0
Step five. You can now remove the front of the cluster, it held in place with a couple of clips on the side, and around the display. Just take care not to break any clips as then your display will not work anymore. So now you are just holding the circuit board, and now you will see the chipset that you have. It will be printed on the chip.
Step six. Modify the CAS4 you bought out of China. Start you soldering station and only disconnect/remove the yellow resistor as shown in this video.
https://www.youtube.com/watch?v=VSjGOXzRUz4
Step seven. Before starting note the way your chip is located on the circuit board. Desolder your chipset from your new cluster. This sounds really hard, don't worry about it just attach the smallest nose on your hot air station and set to 300 degrees and just keep moving it around above the chip and then it comes off really easy. Just make sure you don't bend any of the legs.
Step eight. Insert the chip in your modified CAS4 programmer. I tried with the clip, but this was no succes. The correct way is to push the eeprom reader down, insert the chip that it is properly inserted.
Step nine. Load the R270 software and read the information from your chipset. Really important save this file and make a backup copy. This way you can always have a backup to restore to/from. After this is done, remove the chip from your R270 and put it aside.
This is where you need to be in luck and where i struggled for a while!
Step 10. Modify the HEX file you see. First thing you need to search for is the VIN. In my case it was located on line 60. I changed this to FF. as later we will be using NCS Expert to copy the VIN from the Light Control Module to the chip.
Step 11. Insert one of the new chips into the R270 and write the modified HEX to your new chip. This should not take more than a couple of minutes, and it will confirm that it has written the file successfully.
Step 12. In the R270 software the option is to adjust the mileage. I changed this to 500 km as I want to be sure that it would not error out and when the unit is programmed correctly it will adjust the milage anyway. Let the unit program. Again it should not take long and should come back with a successful write.
Step 13. Solder the new chip back on the circuitboard. Pay attention to the way the original chip was mounted. Again use hot air station and take your time. I am absolutely no expert but with taking time and a magnifying glass i was pretty happy with my work.
Step 14. Clean your cluster insides. They are open so might as well make them look good.
Step 15. Reassemble the cluster with the front. Just to be safe, I also cleaned the display connectors with rubbing alcohol.
Step 16. Attach the cluster to the car, it should show you the 500 Km but with the tamper dot. Not to worry.
Step 17. NCS Expert time! you'll need to code the cluster to your car. The best way to do this is to use NCS Expert with an Expert Mode profile, or Revtors Profile. To do this, open NCS Expert and load the profile, then click the F1 button for ZCS/FA, then click ZCS/FA f. ecu. This will ask what chassis the car is, then ask what module to read it from. Choose ALSZ. Once it reads the ZCS/FA from the car, click the back button on the lower right of the screen. Now you have the option to "Process ECU", so select that and then select IKE or KMBI, depending on what is available. Now, click "Change Job" and select "FGNR_schreiben" and execute the job. Wait for the job to say "finished". Next, change the job to FA_Write and execute the job. Wait for it to finish again. Finally, change the job to "SG_codieren" and execute it. This one will code the cluster to the defaults for your car. Once coding is complete. Your new odometer has no more tamper dot and will show the correct mileage as it has taken this from the other units.
Step 18. Use INPA to read out all your errors and clear them. You can also use a tool like Carly, BMW Scanner 1.4 or many other tools but I prefer INPA. Clean up any errors and you are good to go!!
Again, all above at your own risk.
In hindsight, considering the hours spent researching and working on it... it would have been easier to actually find a company to do it for me. So hopefully this will help some other people out there.