Just wanted to put it out there, some may already know this, I did not. I recently had to replace my phone like immediately because old phone was no longer operational. I bought a factory unlocked model. I got an S26 Ultra and the software version ends in U1. I was a First Net subscriber and found out that any unlocked mon carrier specific phone for all brand is not approved for the network. As soon as the IMEI numbers were ran it came back Black listed and not approved. Apparently the specific software requirements are not embedded in the unlocked versions. So I had to switch to a medical signature account. I have forwarded these complaint to Samsung Corporate, I believe this is unfair and at least should have been made known to me, which it was not. My suggestion is that that software should be embedded into all phones . This has caused me a great deal of issues. If Apple and Google can provide it on their unlocked phones , then there is no reason Samsung cannot follow as well. This shouldn't be an issue about what should or shouldn't be added on a phone , this is public emergency safety and not just some bloatware apps that have some financial gain between Samsung and a third party company or carrier. Rant over !
From quick search I did I found: " AT&T's network core sometimes requires carrier-specific firmware for advanced features like VoLTE or 5G HD Voice, leading to connectivity hiccups even if the hardware is compatible. " So this looks like AT&T issue
From what I've learned from the First Net Reps is that all the Carrier phones , no matter which one has this security software built into it. The phone that I replaced was a Verizon Note 20 Ultra. It is a specific software that links to band 14 which is one of the core bands First Net uses.
