Dual-Sim, choose SIM for bluetooth HFP connection

I use Sailfish X with bluez5. If you have bluez4 it might be different issue but if first is the case, perhaps look into bluetoothctl (if you are familiar with command line tools) there is more flexibility.

I don't have this same problem (single sim here), but I looked a lot into the HFT stuff and sometimes it helps to delete the .pulse or .config/pulse directory and reboot, so that it may recreate properly.

I then would tell pulse audio which is the source to connect to - I did it for A2DP, but should be similar for HFT. It looks like PA is picking whatever source available. It sounds like you have bluez5

good luck

Thanks. I'm very familiar with BT CLI tools (unfortunately - having struggled to get A2DP working on a BananaPi!). There's more to it than fiddling with pulseaudio, though. The sound might go through PA but the operator/signal/contacts obviously don't. But maybe it's possible to disable HFP on SIM 2. BT and pairing applies to the whole phone, though, not each SIM AFAIK.

Ideally the UI should be in the car, when you connect - or perhaps pair; it should ask which SIM to use. I wondered if anyone has a car that does that?

On further investigation, SIM selection (as described in my link above) is probably part of Sim Access Profile (SAP). initial support for SIM Access Profile was added in BlueZ 4.91.

Still not clear what bluez version you have. If it is bluez5 the HFT is in ofono. So those 3 must play together. It looks like ofono is offering HFT for second sim, because perhaps 2nd sim is discovered later.

Try disable/enable sim1 and see if it gets connected.

I don't know exactly how it works - you need to look into the code to get it right or track the behavior and ask for bug resolution.

I had to always do following on my PC to be able to get A2DP working from phone to pc

pactl list short
pactl load-module module-loopback source=bluez_source.xx_xx_xx_xx_xx_xx.a2dp_source sink=alsa_output.pci-0000_00_1b.0.analog-stereo

regards

With the help of my auto-enter-pin script, you can automate the activation of SIMs in the order you wish at boot. This means you can use DaveRo's workaround while keeping a pin lock on SIM 1.

This workround does not, in fact, work - or not reliably, or not any more on my Jolla C 3.0.1.11 Yesterday the car connected to SIM2 despite SIM1 having been activated first. On the previous occasion I had connected SIM2 to the car by disabling SIM1. Maybe it 'remembered' that.

The connection will be don with the last activaed SIM. So after reboot the activation sequence is SIM1 then SIM2 and SIM2 will be connected via BT. If SIM1 is temporarily disabled, it's the last activated SIM after and will be connected via BT.

(reliable) workaround: disable and reactivate the preferred SIM before connecting to car, also to have the connected SIM displayed correctly. Otherwise the car display will switch to connected SIM with next call. It's a fiddling - even in 3.2.1 ...

If I recall correctly HFP is registered to bluetooth via ofono - so disable the sim and restart ofono should be enough. I'm not sure how you can easily restart ofono though - I was thinking there were an option under utilities, but just checked and there is none.