[Samsung Galaxy S7 Questions and Answers] nadiawicket:
Was on Sprint and decided to change to T-Mobile and now the new T-Mobile SIM Card is unrecognizable/unable to register. This means I am left with no Data/Voice/Text. Checked on a T-Mobile S9 to verify its not the actual card. Works flawlesly, so its not the actual SIM Card itself. 3 months back and forth on and off wrestling with both carriers. Sprint claims device to be Unlocked. T-Mobile claims that its impossible because it sais "device not registered" when I try to make a call. They assured me that this happens only if its locked. Sprint has claimed various times that my S7 (non edge) version is Unlocked for both Domestic and International. Phone was rooted. I was so angry at Sprint you wouldn't even believe it.

Tried flashing T-Mobile FW as the internet suggested. Got it to work and remove the Sprint logo from startup and the super annoying "hands on activation" every 5 minutes thanks to the T-Mobile FW. Problem is that it still does not recognize the SIM Card. Went back to Sprint FW because Sprint rep number zillion said I needed to do a profile update in order to make sure that it got correctly unlocked. I couldnt do this because I had the T-Mobile FW (Oreo 8.0 SM-G930T G930TUVS8CRL1_G930TTMB8CRL1_TMB) and it does not even allow you to do the usual System Updates nor does it allow you to even edit APN's. So I tried to go back to Sprint FW from SamMobile Official (SM-G930P_1_20181203144853_tiy1p0tkd7_fac) and actually got it all installed (all binaries) and now the phone does not display the Sim Card "error" icon on the top left nor the circle crossed icon on the top right. Problem now is that the phone automatically power-cycles in about 2-3 minutes after we start the usual "First Time Use" sequence where you fill your Google User Name and Password and sign the EULA, other first time things, etc. I can't just put in my Sprint SIM Card because I threw that one away as I unsuspected that it would be necessary in order to maybe try to use it to get it past the 2 minute barrier on going back to Sprint FW. Next step would be to take it to a Sprint store and have a Sprint SIM Card inside the phone and see if the 2 minute barrier doesn't happen so I can do this new "Profile Update".

I then tried flashing what I believe to be the non carrier specific official non bloatware Samsung FW SM-G930U. Now the issue is that the version I downloaded from these forums (https://xdaforums.com/galaxy-s7/how-to/g930u-official-stock-firmware-android-8-t3821152) was not able to flash anything but the CP. So Im now going to try the latest SM-G930U which does have the updated BL.

Checked out the forums for T-Mobile and they all assume you can at least edit APN's and have some sort of connectivity. I can't even get my SIM Card working AT ALL. Can't edit APN's because the Sprint FW auto resets every 2 minutes in the new user thing and the T-Mobile FW does not even have the ability to do so. Tried starting on Safe Mode, tried removing the Sim Card and discovered phone wont even boot without it.

Will now continue to check out the SM-G930U latest FW in hopes that this will in fact allow me to flash the non carrier specific binaries which I assume should be able to fix the problem. Trying out https://xdaforums.com/sprint-s7-edge/how-to/g930u-firmware-bootloader-update-device-t3863219. At SamMobile (https://www.sammobile.com/firmwares/galaxy-s7/SM-G930U/BST/download/G930UUES8CSA1/255180/) theres like a zillion to choose from. Any suggestions?

Been getting the fused 8 binary 2 (and other numbers) glitch a couple of times when trying to flash anything. I assume this is due to the BL. Heard QualComm S7's were invincible and I'm afraid its a QualComm because it sais QualComm SecureBoot: ENABLE on the top right of the ODIN Download screen.

Top Right of Download screen:

ODIN MODE (HIGH SPEED)

PRODUCT NAME: SM-G930T

CURRENT BINARY: Samsung Official

FAP LOCK: OFF

WARRANTY VOID: 0x0

QUALCOMM SECUREBOOT: ENABLE

AP SWREV: BB(2, 1, 1, 1, 1) K8 S8

SECURE DOWNLOAD: ENABLE

You have any suggestions or insight as to how to have the T-Mobile SIM Card recognized in the unlocked Sprint S7?