My FP3+ had two sons installed. SIM 1 is a Three Mobile on a monthly contract. SIM 2 is a Vodafone PAYG.
I like to keep SIM 1 as my preferred SIM for calls, data and texts but each time I restart my phone SIM 2 becomes the preferred SIM for calls. This problem has only occurred since upgrading to Android 11, I think.
Any ideas?
It’s interesting to note that my wife’s FP3 doesn’t have this problem. Her two SIMs are Three Mobile and Giffgaff.
There was a similar problem with the FP4, so maybe the solution is the same as well: Do both SIMs have PINs set or maybe only SIM2? In that case try to set PINs for both of them.