Google released the March 2023 security patch update for its Pixel 5 and Pixel 7 series earlier this month, and the update for the Pixel 6 series and Pixel Watch has been released recently. One notable feature in the March monthly Pixel firmware rollout is regression. If you are a Pixel 4 or Pixel 5 user then this is bad news for you.
Qualcomm-based Pixel (Pixel 4a 5G / 5 / 5a) devices have lost 5G standalone connect capability since the March 2023 Android update. It appears that Google has decided not to enable VoNR on these units. People believe that since the phone may be connected to a 600 MHz (T-Mobile) N71 connection over a viable LTE signal, this may result in a scenario where the phone cannot dial or receive phone calls.
Sad that if Google really cared these phones would probably do just fine with VoNR. With hacking into QPST, sites like Band.radio have proven that VoNR works on them. Google waited until after the Pixel trade-in Fire sale to do this, so if you have Tensor, you can easily continue using 5G SA.
This seems to be a smart move, as T-Mobile IMEI has blocked these phones from using the N41 and N25 in 5G SA mode… so you basically need to use the N41 for cell mapping and rural data usage. Free band locking found on 5G N71. Sadly downgrading is the only way to restore it.