[Verizon HTC One (M8)] avg2424:
Hello all,

I have recently gone on a quest to get a Verizon M8 to work on T-Mobile. I went on this journey because I had broken the screen on my Tmo M8 3 times already and was tired of replacing the cheap knock-off replacement screens (the oem glass is far superior). Well pricing for the tmo m8 was higher than I wanted to pay and used phones weren't in great condition. I found a Verizon M8 in great condition for a price I could live with.

So what, you might say, the stock Verizon is unlocked. Yes, to a certain extent. You will get annoying Verizon bloatware (which most can be removed) and you will get an annoying prompt that the inserted sim is not a Verizon sim (which can also be removed with some work).

The phone will act a bit weird however and settings are slightly different if you're used to a Tmo M8.

So I started experimenting to get my T-mobile M8 back (with a Verizon logo on the back)

(See the quick recap on the bottom of this post for the specific items needed and in what order)

First of all, you will need Sunshine to S-Off because stupid Verizon won't let you unlock from htcdev. Thanks Verizon.

http://root.ninja

Second of all, the rom in question is MM. Meaning you will most likely have to flash firmware.

I downloaded a good version uploaded by Santod Mods. The filename is "6.21.605.3_FULL_firmware.zip"

https://www.androidfilehost.com/?fid=24457741883933342

http://xdaforums.com/verizon-htc-one-m8/development/wip-4-17-605-9-stock-resources-firmware-t3196906

Of course you will need SuperSU

http://xdaforums.com/showthread.php?t=1538053

a custom recovery like TWRP

https://twrp.me

and the venom rom

https://www.androidfilehost.com/?fid=24459283995299420

http://venomroms.com/htc-one-m8/

The process:

I first tried my current favorite Venom, but the install ran a bit different and after boot up, I saw big differences. Rom after Rom had the same issues, they were Roms tailored to Verizon. I'm sure they were great Roms, if you were running Verizon, but I wasn't. Yes I had a Verizon phone, but I was trying to get it tailored to T-Mobile.

I thought I would trick the Roms into thinking my phone was a T-Mobile version.

http://xdaforums.com/showthread.php?t=2708581

I then tried Venom and saw the usual install options (awesome!) or so I thought.

The phone wouldn't boot, it would just go straight to the bootloader. Everything else I tried flashing didn't bring the phone back to life. That's when I learned that trying to use certain Tmo roms on this phone cause this issue and the only way to fix it (IF you are going with MM) is to reflash the firmware (and reinstall custom recovery).

So I started digging into the rom zip to see what was different. It looks like a temp boot.img might be needed for the Verizon M8.

So what I did was copy the Verizon temp boot image from the venom rom zip and pasted it into the tmous folder

Copy the tmp folder located here: ViperOneM8_5.0.2.zip/additions/carriers/Verizon/

To here:

ViperOneM8_5.0.2.zip/additions/carriers/tmous/

And save

Special note: you may need to format the media you are using to a different file system if the file size of the modified zip goes over 2GB (or just delete another carrier folder (like Sprint))

Run the install in custom recovery and select the T-mobile option when it comes up.

Tada

You now have a Tmo m8 (with a Verizon logo on the back) with WiFi calling!

Final special note. Tmo data doesn't play well with custom MM roms, from my experience.

You will need to use DFS to adjust radios to prevent a certain data lockup that sometimes occurs when moving between data rates. When the lockup occurs, you will need to toggle airplane mode (or data connection) off and back on.

When I contacted HTC about this, they advised me to try a new sim, which I haven't yet, so the disclaimer stands for now.

Quick recap:

Step 1:

Get S-Off

http://root.ninja

Step 2:

SuperSU

http://xdaforums.com/showthread.php?t=1538053

Step 3:

Change the model ID to T-mobile

(this must be done with a fully booted device so it is crucial this be done before flashing firmware)

http://xdaforums.com/showthread.php?t=2708581

Step 4:

Most likely flash MM firmware

http://xdaforums.com/verizon-htc-one-m8/development/wip-4-17-605-9-stock-resources-firmware-t3196906

Step 5:

Custom recovery

https://twrp.me/

Step 6:

Customize the venom rom zip

(steps in post above)

Step 7:

Install the rom and select T-mobile settings when prompted