I fixed my samsung galaxy s20 on the new 5G boost mobile network
I am posting this as an epilogue that I hope will help others.
I have been through a week of he** after communicating with over a dozen boost mobile representatives trying to get my phone to work on the new network.
None of whom had the ability to help me resolve the problem of switching from the old network to the new one.
Every representative wanted to start over from square one diagnostics (or have me buy a new phone).
Even the most basic business ticket system should issue a case number on the first call that is not closed until the issue is resolved.
As I noted in a prior post, the culture over there must be terrible.
I am fairly tech savvy and I had a week on my hands to get this resolved, this is not for the faint of heart.
What I did could easily brick your phone, I strongly recommend getting assistance if you can.
By this point I had done a complete factory reset and my wife was telling me to give it up.
I didn't see that I had much to lose. I don't consider a phone that expensive a throw away item.
Let me point out here, that my phone is 100% legally mine. It is paid off and I have had it on boost for over a year. Boost issued an unlock case and a boost representative even insisted to me that it was unlocked, it was not.
After another day of research, I decided to try and install an sm-g981u1 firmware update.
I found this version: https://androidfilehost.com/?w=files&flid=305578
As it turns out I had had conversations just yesterday with the guy who posted the binaries about my phone problems.
He seemed honest so I trusted the zip file.
There are many steps involved in the update, I won't go into it because the info is already on the internet and there should be enough search keywords here if you feel you are up to it.
Do NOT try it if you're not handy with Microsoft windows and USB connections and are willing to have a phone that is in worse condition if the process goes wrong. I had to search out and download three zip files that were ~5MB altogether. The first attempt failed because my USB connection was flaky, Luckily the second go round worked.
Note that if you do the unlocked firmware update you will get many updates that are not available on the boost mobile firmware (another bug or 'feature'?). I think I got about a dozen, I was starting to get worried, but the phone eventually stopped updating. My phone went from Android 10 to Android 11 for instance.
The Samsung/Boost Mobile 'locked' firmware that came with my phone was the problem. There are really only two possibilities, the most likely is that the original firmware is buggy, indicating bad QA being done at boost mobile. Buggy locked firmware is boost mobile's problem and responsibility. But considering the cost to fix all of the phones out there with the issue, I'm sure they would rather look the other way, pretended it doesn't exist and take the publicity hit. They might not even realize the full scope of it.
I have no idea if a similar upgrade will fix other boost mobile phones (besides the S20). Several people are reporting similar issues on different phones when 'forced' to upgrade to the new network.
I hope this helps someone.
My phone is wonderful since I fixed it.