I think the echo problem could be caused from both phones having speaker phone turned on.
In which case it gets more complicated, if you turn down the microphone sensitivity it may reduce the echo,
.... but then you may have to hold the phone closer to your mouth.... hmm...
.. > ( You put it on speaker phone so you can set the phone down... )
As far as modem related problems go,
it appears on the Brave Heart Edition you risk corrupting the modems firmware by simply turning off your phone.
Perhaps that explains why the earlier versions of Phosh/Debian and Mobian operating systems both worked fairly well on my phone.
( But when I went back to retry these previous releases, they no longer work like they did )
Calls in & out, and texting in & out were working.
Now I cannot receive text.
Hopefully your UBPorts C.E. phone is more dependable...
Your tests do give a good indication of the current state of the operating systems you test.
In which case it gets more complicated, if you turn down the microphone sensitivity it may reduce the echo,
.... but then you may have to hold the phone closer to your mouth.... hmm...
.. > ( You put it on speaker phone so you can set the phone down... )
As far as modem related problems go,
it appears on the Brave Heart Edition you risk corrupting the modems firmware by simply turning off your phone.
Perhaps that explains why the earlier versions of Phosh/Debian and Mobian operating systems both worked fairly well on my phone.
( But when I went back to retry these previous releases, they no longer work like they did )
Calls in & out, and texting in & out were working.
Now I cannot receive text.
Hopefully your UBPorts C.E. phone is more dependable...
Your tests do give a good indication of the current state of the operating systems you test.