Windows 10: Cellular setting for SIM1/SIM2, how to change the default SIM via registry

We sell Surface Go 2 systems for use in hospitals, they are running our own software with a custom shell, so the customer has no access to Windows at all.All our customers use physical SIM cards for broadband connection.The Surface Go 2 has a eSIM and an additional slot for a SIM Card.In Windows 10 under Settings --> Cellular you have an option for which SIM to use dropdown menu SIM1physical card and SIM2 eSIMSadly by default it is set to SIM 2, which is the eSIM, so the customer with a physical SIM can´t access the internet.Again, the customer has no access to Windows/Settings to chan

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Call dropped when making call using SIM1 and using data through SIM2

I am using Lumia 635 (i.e. Dual Sim version of 630). My current setting is SIM1 for voice call only (data disabled) and SIM2 is a data only SIM

Every time when I try to call using SIM1, if there's data flow in SIM2, it's 100% that the call will drop after SIM2 icon is gone at the top status bar. If no data is flowing the call will go through smoothly. However for receiving call there's no problem
experienced.

My phone is Lumia 635 (RM-978)

OS version 8.10.12397.895

Anyway to resolve this problem? It's really annoying...

Thanks

C.Y. Wong

 

Can't use my Lumia 640 XL Dual sim as a WiFi hotspot

Same problem on my Lumia 650 Dual SIM, but only if I use SIM2 for cellular data, works fine if I use SIM1.

I had the same issue on my old Lumia 630 Dual SIM, but in that case I solved setting a custom APN (with the same settings of default APN) on SIM2.

Alex.