it depends why the error appears.
- if hardware (PHM) is ok and just the SIM is not supported (it's too new or some other reason) then it will work.
- if there is a damaged ribbon cable between PHM and SIM slot then it will also work (i don't use it).
- but if PHM is damaged (somehow) then it has to be repaired or replaced.

it's not easy to find the reason. if you know somebody with SIM which works then you can test it. you can also send the PHM to me and i can look on it. if ok (or i am able to fix it) then you can buy the module from volvocesky, i will add it into the PHM and i will send the PHM back to you with the module already implemented.

Sims worked fine for years in it...then it stopped one day.

Hoe much are they?

sorry for delay. regarding the price please ask volvocesky (info@volvocesky.cz). regarding the repair of the PHM then if it's possible then on 80% free and if not then probably not more than 20€ (i will let you know after a test).
i have development piece of bt module so i can tell you if it's ok before you buy it ;) .

the new version after a longer time. it looks like there are not so many changes but some parts of the code are quite rewrote.

how-to update (also the bootlaoder): here (turn the english subtitles on)

v2018-04-13_1
Fixed
- Bluetooth: Voice command activation on iPhone.
- Bluetooth: Possibility to set the module just for Hands-Free (HFP).
- System: After the bootloader is turned on then it will stay active even if turned on again (if power is turned off). The only way how to switch it back is to upload proper version of the firmware.
Updates
- Some modules has been fully rewrote.

if the bootloader is not updated (after the firmware update) then it is not possible to turn it on.

When I update the bootloader with the boot_loader.btb from the v2018-04-13_1 archive, I end up with a "vbvb2016-10-01" bootloader.

Is the wrong file in the latest archive?

Updating the bootloader with the file from the v2017-12-17_2 archive does change the version to vb2017-12-15.

did you see "BTLDR OK" message on the dashboard after the update (instead if Volvo BT or name of connected device)?

edit: did you use android cellphone or laptop (with windows)? if cellphone then what is the manufacturer? if samsung then you are lucky that it still works (because samsung is not able to do things properly).

Yes. The BTLDR OK message appeared every time correctly. I updated the bootloader using a laptop running Windows 10. I did not try to use my Samsung phone because of the warnings in the manual.

I did a number of update/downgrades of the bootloader and every time I used the bootloader file from the current update on your Google drive, I ended up with "vb2016-10-01" bootloader, and every time I used the previous one I got "vb2017-12-15" in the DIM info display.

So I would say either the bootloader in the latest download archive is an older version, or it has the wrong version number internally.

one more question ;) .
was the module turned off after the bootloader is updated? or did you check the version directly after the update? i guess that it appears if you do the update and not turn the module off (small bug from my side).
do the update (just bootloader), turn off the ignition, lock the car and wait at around 2 minutes. then turn it on and check the version. it should be ok.

the version of bootloader in the package is right.

No, I did not turn it off for 2 minutes.

I will try again tomorrow to see what happens when I do.

Can you explain what this bootloader actually does? Is it necessary to update this as well for normal operation?

If I can put a feature request in here: it would be very welcome to have an easy way to switch between two paired bluetooth phones. I have a company and a private phone, and mostly the private phone is connected, but I would like to be able to switch easily to the other phone if I happen to have a call come in on that phone while driving.

The fastest way I have found so far is to manually disconnect the first phone (using the phone), and then connecting the second phone by pressing the green key and selecting that phone.

the bootloader allows you to flash the main program. it's on the different space so while the update it's not re-wrote. so the main program is only possible to update from the bootloader and bootloader is only possible to update from the main program. for normal operation the bootloader is not required.

regarding phone switch:
at the moment you can manually disconnect phones by dialing "***". it will disconnect all connected phones. if you have had a ericsson modem in PHM then it's possible to connect the phone from "dialled calls" (green, and then green button).

first new potencial feature:
i can add a feature to disconnect a master (first connected device with HFP profile) and connect the HFP to the slave (second device). so it will create the master device from the slave and the original master is disconnected. for example "##*".

second potencial feature:
i can add a feature to remain both connected. it will only swap the HFP from the first to the second device. so it will swap the master and the slave. for example "*##".

at the moment i have to do something else before so it can take a while. but it's not a problem.