Connection bars not working properly since pie update

[golharbinger]

The connection bars for my provider (Telstra - Australia) seem to be broken after the pie update. My connection is showing 0 bars, but the signal strength is actually -100 dBm according to the service menu in the phone, which is pretty good, so it looks like it's just those bars aren't indicative of reality. It worked fine with the previous firmware.

I've done a bit of digging and it looks like carriers/OEMs can define what those bars mean. According to the settings for Telstra in the Android code itself, -100dBm should show 3 bars. It seems that the Sony is not including those settings in its carrier configuration app. https://android.googlesource.com/platform/packages/apps/CarrierConfig/+/master/assets/carrier_config...

Is it possible to get the Telstra settings added to Sony's carrier configuration app?

[golharbinger]

Was just reading a bit more about the technical side of this, and it might not be possible without Telstra's involvement as there needs to be some code signing. Maybe Sony can just improve the default behaviour by using some more sensible default values for the lte_rsrp_thresholds_int_array.

[VeronikaXZ1C]

I have the very same problem in Hungary, with service provider 'Telekom'. Most of the time I have zero bars, sometimes one.

I also have problem with 4G: tried to download Internet settings, rebooted the device, but does not work. Worked just fine before the update. Is there a solution for this problem? 

[golharbinger]

I've been digging into this more over the past week and in my case at least, the issues doesn't seem to be with the lte_rsrp_thresholds_int_array values themselves, but the fact that RSSNR values are being used to re-evaluate the signal bars. So when I actually have a good signal strength and quality from the tower, the OS is overriding the signal bar strength based on the SNR.

I don't have a XZ1C on Oreo anymore to test with, but I've tried my sim in a Pixel 3 on Pie and a Samsung S8 on Oreo and the signal bars work properly on both of those. Sony can fix this by changing their custom Android code to ignore SNR in the signal strength calculator since that value is unimportant for LTE connections (RSRQ takes the SNR into account).

I realise this is just a forum and there's no chance Sony will actually look into and fix this based on this post, but for anyone else experiencing weird behaviour with their signal bars since updating to Pie, this could explain your problem and you can bring it up with support like I'm about to do.

[golharbinger]

If anyone is interested, the key you need to set in the carrierconfig (or in the vendor overrides) is:

<boolean name="use_only_rsrp_for_lte_signal_bar_bool" value="true" />

You can't do this without building android yourself, unlocking the bootloader and flashing it to the device, but it works. It'd be nice if we didn't have to go through all this, but it is what it is.