Hello,
I was getting a little frustrated that since moving from Three to O2, I was no longer able to access data (WhatsApp, Waze / Google Maps etc) while speaking on the phone. It seems that the data symbol would disappear once making a call and therefore I was unable to get a data connection.
I had a read through this post which suggested it could be due to my device falling back to 2G during calls. However within my choice of network modes, I had no way to disable GSM without disabling LTE.
I tried an app called Activity Launcher which allows access to a number of phone settings not usually visible (this may well be one of many), I'm sure there are other ways of accessing the information within the app but this makes the whole experience quite straight forward. By going through 'All Activities' -> 'Phone' -> 'Disable 2G', then enabling the feature this seems to have blocked my phone from defaulting to 2G for calls and therefore allowing me to continue with data whilst on the phone.
I imagine this all comes with risks, for example I believe that 2G plays more of a role for emergency calls and you're tinkering with phone settings that the manufacturer hid for a reason, but so far so good for me. I'll post back if I suddenly find I have other issues.
Just thought the information may be useful to someone else. FYI I'm using a Samsung S7 with Android 7.0.
Daint
