The HTC 10 that you can buy direct from the company supports AT&T and T-Mobile SIMs from first boot. But with a little DIY, you can get your Verizon SIM to work in it, too — without all the lockdown and bloat.
A few XDA devs were able to make it happen on their devices and have published a guide for you to make it happen on your own unlocked HTC 10.
In practice, it seems pretty simple: open up to the device’s bootloader and fastboot flash the Verizon radio package they’ve provided onto the phone. After checking into settings and a secret Verizon back-end menu, you should be all set. Devs are working on adding advanced calling features onto the phone, but the data/voice/SMS trifecta should be working properly.
We’re directing you to the source link for specific instructions out of respect of the developers — easy as the steps may be, compiling all the materials to make them easy isn’t. If you need to get set up on how to handle fastboot, check this out.
HTC’s very forgiving warranty policies will allow you to do some crazy things with your phone and still get it serviced if you manage to brick it.