Last fall, OnePlus made its official debut into the US market with the T-Mobile-branded OnePlus 6T. It was essentially the same as the international variant, save for a few defining differences. The most notable changes were the SIM tray which only held one nanoSIM card and the lack of an immediate bootloader unlock option. Customers buying the OnePlus 6T through T-Mobile had to first pay off the device completely and have it SIM-unlocked before they could unlock the bootloader. This was a 40-day process at a minimum. Luckily, working around this block was as simple as converting to the international firmware and unlocking the bootloader like normal. Unfortunately for us, OnePlus "fixed" this workaround with its latest T-Mobile phone, the OnePlus 7 Pro.

Although you can still flash your T-Mobile OnePlus 7 Pro to international firmware, doing that doesn't allow you to unlock the bootloader. However, there's a reasonably easy way to unlock your T-Mobile variant's bootloader even if you don't qualify for an official unlock. Our own Daniel Marchena accidentally discovered this method, and it's surprisingly easy to do.

T-Mobile OnePlus 7 Pro Forums

NOTE: This is likely a limited-time opportunity. The process depends on flashing OnePlus' Android Q DP3, and OnePlus will likely patch this method.

Steps to Root the T-Mobile OnePlus 7 Pro

WARNING: this process will erase your data (twice)! Make sure you've backed everything up before beginning.

  1. The first thing you'll need to do is flash your OnePlus 7 Pro to the international firmware. Adam wrote up a quick guide for that here.
  2. Once you're on international firmware, you'll want to download and flash Android Q Developer Preview 3 for the international variant. You can download the firmware here.
    • If everything's gone right up to this point, you should notice that you don't have any service.
  3. Go to Settings and enable Developer Options.
  4. Go to Developer Options and enable the OEM Unlock switch.
  5. Reboot to fastboot and unlock the bootloader like normal. If you're not sure how to do this, Adam has a guide for that here.

At this point, your T-Mobile OnePlus 7 Pro will be bootloader unlocked. If you want to get your cell service back, either flash the Android Pie rollback package (available from the same page as the Android Q DP3 firmware) or install TWRP and flash a custom ROM of your choosing. Daniel tested both Havoc-OS and AOSiP, and they both run great on his device. Just keep in mind that there may be some unforeseen compatibility issues.

If for any reason you need to use the MSMDownloadTool to restore your phone, you'll end up with a locked bootloader and you'll need to start this process over.

And that's it. It's a little more complicated than the OnePlus 6T's method, but not by much. Just remember that this will likely be patched in an upcoming Developer Preview, so if you've been thinking about rooting your OnePlus 7 Pro, now is the time. If you do try it, let us know if it worked for you!