I have run into problem of cell network connectivity sudden total loss. SIM1 and SIM2 not working. Nothing was going to change it whatsoever. No amount of changing SIM cards, swapping, turning airplane mode on and off, restarts, nothing.
I blamed absolute downpour of rain, but it turned out to be wrong lead.
This particular problem will cause Radio to get turned off. This includes GNSS, so no GPS etc.
In order to get information about phone, open phone app, use keypad to enter
*#*#4636#*#*
and then choose phone information.
Phone still see SIM card and you can see IMSI number populated. If you don’t see IMSI, then phone does not recognise SIM card and it is different issue.
I have found one post on XDA, where flex PCB for buttons was replaced and all connectivity was regained.
https://xdaforums.com/t/sony-xperia-1-iii-sim-cards-not-working-fixed.4656203/
I followed this lead and ordered said flex PCB. I have fully functional phone after replacing this flex PCB.
Only reason I post here is to confirm this works, so people can actually repair their phones, if something like would happen to them.
I hope it will help others.
Please mind I am on 3UK, which have no 3G (UMTS) any longer, therefore I switched it off on my phones as well to prevent phone searching UMTS cells.
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