Because there is no OTG port on M8 amlogic s802 tv box, so you can’t use the same root method on tronsmart vega s89, so here is the only method to root the device:
1) Download this zip file and put it on a SDcard. DO NOT unzip it!
Note: It may work on the internal SDcard but I did not test it as you cant write to it from the PC as this ROM does not support Mass Storage.
2) Put the SDcard into the M8 SD slot.
3) Go into your APPs and run the update tool.
4) In the update tool click the “select” button. It should list the file M8_root_update.zip. Click it.
5) Now press the update button.
6) The system should reboot into recovery and automatically install the zip.
However sometimes it reboots to the recovery menu! Not sure why.
If it does, then using the mouse, select “Apply updated from EXT”
Now select SDcard. You should see the M8_root_update.zip file. Select it.
Recovery will then install the update. When done select reboot system from the menu.
Shopping link for M8 tv box is here:
All credit to the great BOB Finless!!!