[Verizon HTC 10 Guides, News, & Discussion] misterk267:
Hello everybody! I thought that given the relative complexity of this task and the difficulty that some users have been experiencing with the process, I'd write up a small step-by-step guide on the matter.

Requirements:

VZW HTC 10 with s-off and unlocked bootloader

Computer running adb/fastboot

This guide also assumes that you have the latest TWRP already installed on your device.

Before we begin, I'll go ahead and insert the standard disclaimer. By utilizing this guide, YOU are choosing to modify your phone. By continuing to read this thread, YOU acknowledge that I am not responsible for any adverse effects that may come about as a result of your following this guide.

Okay, now that the unpleasantness is out of the way, let's get started shall we?

Step #1

Download your preferred AOSP Rom & MM Gapps and place on your external SDCARD. This process shouldn't wipe your internal storage but I'd put them here anyway to be safe.

Link to CM13 thread: http://xdaforums.com/htc-10/development/alpha-cyanogenmod-13-0-unofficial-t3465667

Note: A few users have commented in the Validus Thread, saying that it doesn't boot on VZW devices even with unlocked firmware. I'd recommend going with a different AOSP rom to start with.

Step #2

Download latest US Unlocked firmware package. I'd recommend the NoWipe option so you don't lose data on internal storage.

Link to thread: http://xdaforums.com/htc-10/how-to/2016-05-27-fastboot-flashing-firmware-t3387520

Step #3

Modify firmware package content. Extract the package using latest 7zip. Inside there should be a large number of .img files. Delete the following files from the archive:

cradio.img

radio.img

recovery.img

**NOTE -> I am recommending 7zip and notepad++ for windows users because users have reported success with these tools. For what it's worth, I had no issues doing any of this with Xubuntu Linux's built-in file extractor and notepad application.**

Step #4 Change CIDs so that the CID in the firmware matches the one on the phone. There are two ways to do this. Either A). change your phone's CID to superCID or US Unlocked CID, or B). Change the CID in the firmware to match Verizon's CID.

Method A.

Reboot phone into download mode and plug it into your computer.

Open a fastboot prompt on your computer and type: "fastboot oem readcid" without the quotes - this command will tell you your phone's current CID. Write this down and store someplace safe. Assuming you've never changed it, it should be VZW__001.

Then type "fastboot oem writecid 22222222" without the quotes to write supercid, or look up the US Unlocked CID and change to that instead - this information should be available easily on xda, though realistically supercid is likely your best bet because it allows you to flash firmware from any region/variant without ever having to edit it again.

**Make sure you enter the CIDs perfectly. Ex. supercid should be "22222222" without quotes - that's eight 2's.

Method B.

In the firmware zip file you downloaded, you can open android-info.txt and find the CID in there and edit that instead.

Change it to "VZW__001" without the quotes and save.

Step #6

Rezip the firmware package and rename to 2PS6IMG.zip

Open the firmware package zip again to make sure it is structured correctly. All of the .img files and android-info.txt should be located in the root of the archive. If they are inside a folder, fix this or the package won't work.

Put the package on the root of your external SDCARD.

Step #7 Reboot phone to download mode. The update process should automatically proceed. When done, reboot to TWRP and perform a full wipe. Then, install your AOSP Rom and gapps from external SDCARD. Reboot to system & Viola! Running AOSP!

Some issues you may run into:

1. Can't get through setup because it keeps looping through the same screens.

Solution: enable airplane mode from the power menu. This allowed me to skip through the options and get to homescreen. I haven't heard of anyone else besides me having this problem though, so you'll probably be okay.

2. No signal/service/data

Solution: Go under cellular network settings and change access point to VZWINTERNET, cycle preferred network type between CDMA + LTE/EVDO and CDMA/EVDO/GSM/WCDMA once or twice should fix it. Your network mode should be CDMA + LTE/EVDO when you are finished.

3. Carrier label reads 3107

Solution: Deal with it or download an xposed module to change it. Also, I think one or two of the roms have an option to change this baked in.

4. Rom appears to bootloop

Solution: If the boot animation just disappeared, don't worry. It will come back. Be patient. :)

5. I can't get into recovery after this process to install new rom and old one isn't booting.

Solution: Remove external SDCARD. Boot to Download mode. Then choose reboot bootloader option. From there choose reboot recovery and you should enter recovery.

Happy flashing! :)