If you purchase phones from a carrier, you may be no stranger to the difficulties involved in rooting and installing a custom rom, recovery and kernel on such a carrier locked device. Add to this the extra layer of security that Samsung adds in the form of the Knox counter on its devices, and one can only imagine the roadblocks for enthusiasts who want to play around with their device without losing warranty in the process. It's a slippery slope where you either end up trading the convenience and perks of owning a carrier device in return of a device which gives more freedom, or are restricted to the skill of developers and mercy of exploits to do basic actions like rooting.

Thankfully, if you own a T-Mobile Galaxy S6 or Galaxy S6 Edge, you can still root the latest Android 5.1.1 update without tripping the Knox counter. This root "exploit" comes in the form of an Engineering Bootloader, which is a modification done by Samsung to bootloader files (sboot.bin) which allows their service centers to do flashing and repairs to the device without tripping the Knox counter. The modified bootloader also disables write protection on the device.

XDA Member wonderingabout got access to such a modified bootloader, and could thus outline a way to achieve root for the T-Mobile Galaxy S6 and the Galaxy S6 Edge. The files mentioned in the thread are specific to the T-Mobile Galaxy S6 (G920T) and to the T-Mobile Galaxy S6 Edge (G925T), so do not try these on other devices.

The root method in this case essentially involves flashing the Samsung Engineering Bootloader via Odin on the device. After this, you can follow along the instructions to flash a custom kernel, or for the S6 Edge, flash TWRP and a different custom kernel. The steps as mentioned in the thread are as follows:

If you plan on using the Unikernel to root your g925t or g920t on 5.1.1 use these steps:

  1. Install Samsung USB Drivers if necessary.
  2. Put phone into download mode. Power phone off then press and hold Volume down, home and power keys at same time until you see warning screen then let go and hit volume up one time.
  3. Plug phone in and wait for drivers to install if necessary.
  4. Open odin you should now see phone's modem port highlighted in blue.
  5. Click on BL tab and select correct sboot.bin that you downloaded above. Then click start.
  6. When phone comes back on power off again and put into download mode.
  7. Open odin again and this time select AP tab and select UniKernel file and click start.
  8. That is it!!! When it comes back on phone will be rooted. To verify that knox has not been tripped go back to download mode and it should still say KNOX WARRANTY: 0 (0X0000)

If you plan on using Aou's Kernel and TWRP to root your G925T on 5.1.1 (DO NOT USE THIS FOR G920T) use the steps below:

  1. Install Samsung USB drivers if necessary.
  2. Copy and Paste SuperSU v2.49 on the root folder of your phone's internal memory.
  3. Put phone into download mode. Power phone off then press and hold Volume down, home and power keys at same time until you see warning screen then let go and hit volume up one time.
  4. Plug phone into computer and let drivers install if necessary.
  5. Open odin and click on BL tab and select sboot.bin file for g925t and click start.
  6. When phone is back on put back into download mode again.
  7. Open odin again and this time select AP tab and flash Aou's TWRP file and hit start.
  8. When phone is back on put phone into download mode one last time.
  9. Open odin and select AP tab and select Aou's v4 kernel and click start.
  10. When phone is back on unplug it and power it off and put into recovery mode (Volume up, home and power keys)
  11. When TWRP recovery is open click on install tab and select supersu file and swipe to flash it. then reboot phone to system.
  12. That is it!!! When it comes back on phone will be rooted. To verify that knox has not been tripped go back to download mode and it should still say KNOX WARRANTY: 0 (0X0000)

XDA Member wonderingabout stresses on the fact that the order in which the files are flashed is important to achieve root without tripping the Knox counter, so be sure to go strictly in that format. As a general warning, flashing modified software (and often untraceable as far as source goes) on to devices has its own share of risks, so do your research properly before attempting.

To follow along the discussion as well as get the files for download, refer to the forum post.

Were you able to root your T-Mobile Galaxy S6 or Galaxy S6 Edge with this method without tripping Knox? Let us know your experience and thoughts in the comments below!