PinePhone Carrier Support
|Warning:||MMS doesn't currently work in any distro on the Pinephone by default! This means images and group chats will not work in text messages.|
|Warning:||Call audio is currently bad quality as there is a clock mismatch from the modem to the mainboard, this should be resolved soon.|
This page contains hints on setting up cellular network connectivity for specific carriers. For more general information, see Modem and carrier support. For the APN settings see PinePhone APN Settings.
According to this page, T-Mobile's primary frequency band for the United States is 12 (700ac MHz).
T-Mobile's bands and protocols are summarized on this page.
While the Pinephone's modem does support all LTE bands that T-Mobile uses in the US (And is one of the best choices for band support with the Pinephone's modem in the US), VoLTE is still listed as "Under development" by the modem manufacturer. T-Mobile's system also does not list the Pinephone as a compatible device due to this lack of official VoLTE support. The modem is capable of working on T-Mobile with VoLTE support enabled "unofficially" however. (It's also very possible that the manufacturer of the modem will eventually add "official" support)
Cricket wireless is a MVNO that uses AT&T's network. VoLTE is fully supported and the pinephone is considered a compatible device in the US by the carrier.
According to this page, Verizon's primary frequency band for the United States is 13 (700 MHz).
Verizon's bands and protocols are summarized on this page. Verizon officially says:
This carrier only accepts approved devices on its network. Even if a device supports some or all of the required frequencies for this carrier, it will not be able to connect unless the device is approved for this network. Check with the network operator to confirm whether a device is approved or not.
But the truth is that with any Verizon-Approved burner phone, you can activate a Verizon SIM and swap it into your PinePhone. Verizon does not care about what IMEI your phone has at all once the SIM itself is activated. 
VoLTE also seems to work as well, calls sound a lot better after enabling it using the steps from The postmarketOS Wiki.
According to this page, AT&T's primary bands are 12 and 17 - 700ac and 700 MHz respectively. The PinePhone seems to work out-of-the-box with AT&T. Activating a SIM works. Calls and SMS messages work. VoLTE is as yet untested.
The FrequencyCheck model page does not list either Pine64 or the PinePhone.
T-Mobile's system does not list the pinephone as a compatible device due to the lack of official VoLTE support from the manufacturer, despite the fact that it does work.
MMS doesn't currently work in any distro on the pinephone by default. This means images and group chats will not work in text messages.
https://github.com/smaeul/linux/commits/patch/sun8i-codec-1-new - WIP fix for audio mismatch