VZW S6 to TMOBILE S6 - need stock ROM

[mannybz]

I have the Samsung G S6 running Android 6.0.1 with Sec Patch level 9/1/2016.

It was purchased via Verizon Wireless and now I have moved the service over to T-Mobile,
Installed the sim... configured the APN.. etc.. it all works on tmobile's network and so forth.. However I an unable to perform any system updates.
I'm sure this has to do with the fact that it's a VZW rom and not a T-Mobile ROM.

I would like to flash this hardware to a t-mobile ROM... but before I do... I thought I would ask a few questions.

1. Has anyone ever flashed a ROM on the VZW carrier and moved it to another carrier.. IE, t-mobile on the S6?
2. If so, where can I obtain the STOCK rom for the S6 standard ROM for T-mobile's network?
3. What issues, if any, were encountered?
4. I have the t-mobile SIM and all is working accordingly but, I still get an alert on boot that the SIM is not a Verizon Wireless SIM.

Thanks in advance.
I did a quick search through the forums but I didn't find anything specific.

Manny~

 

[mannybz]

anyone? bueller? bueller?

 

[Jolly Giant]

bump same question.

 

[Aquila]

Just put a Verizon sim in it to do the update, the sim doesn't have to be for an active line. That'll get the updates, then simply swap back. Is the Verizon S6 bootloader even unlockable?