[Upgrading, Modifying and Unlocking] honzazkrumlova:
I have to agree with Erna1, there really IS the problem with oem unlock, since this command mean DO THE FACTORY reset/wipe. I have followed all steps, sucessfully boot to TWRP, install SuperSU zip from SD and after reboot, Wipe process starts. After wipe finished (by the way, 3-4 minutes of fear while wipe process comes this time without any logo or info displayed), system comes in original state, without any signs of supersu.

Yes, I also tried to install supersu from Play, no success (installed, but after supersu started, report "Binary not installed, this is problem".

After some more reading in forum, I reallized, oem unlock is onetime needed step and the factory reset, which it cause, cancel all I do later (in TWRP).

I guess, 0xAF didnt tried these (#1 post) step on unrooted/locked device, since testing it repeatedly, so this effect was not vissible.

OK, I suggest to edit #1 post with this:

- after fastboot oem unlock, just reboot and let the tablet wipe itself to factory state and after initial screen (Gm account, etc...), start again, just omnit the "fastboot oem unlock". Boot TWRP, Install SuperSU and after finish, reboot and voila .... supersu installed, root OK (as root checker or terminal/su said).

For those, semi-begginer, as me, maybe some more explaining info for the process.

0. Prepare SuperSU zip file on your SD card (http://www.supersu.com/download, ZIP version, NOT APK one)

1. Enable Developer menu

(Setting, About tablet, tap 10times for item Build number, until message appeared)

2. Go back to setting and enter newly opened option Developer options

3. Enable OEM unlocking and USB debugging (asks for extra OK)

4. Now, connection - you need USB cable, installed drivers and ADB software....

5. About the driver - there are 2 (or more) ways to do it. Install original driver, stored in tablet or use generic one (read below).

6. After you enable USB debugging and connect tabled, your PC offer CD (virtual) and install some software from it - drivers, this is the option 1 (just jump to 8, for faster solution)

7. To install original ADB software mean to install Android SDK, thounds of MBytes (plus Java)..... this can be done faster (read 8)

8. Both of these can be done same time with quite smaller and faster "15 sec ADB", look at

this thread and follow that instruction.

After that, driver and adb is installed.

9. For pro's, its invisible, but> to force tablet to connect in that special USB mode, after plugging tablet to USB and PC, in menu (select USB mode), change to PTP.

Soon, tablet asks "Allow USB debugging", followed with some hexa number. Check Always allow and confirm OK.

FinalEdit: I just rooted 4th same device and make this clear. Although I am IT, I am no linux/rooting guru, maybe somebody can explain, but how this unclear step "to force tablet to display USB debig dialog with these numbers" worked for me:

a) once, you install drivers and connect tablet, Windows tries to find drivers and that state is little bit saved - and things can get more complicated. So follow steps exactly...

b) do not plug tablet to computer. First of all, install drivers

c) speaking about drivers - I installed Lenovo USB drivers (LenovoUsbDriver_autorun_1.1.19_user.exe), and how to get this file? Well, you probably can download it somewhere from lenovo website, but to be sure, you can download it from tablet itself. In case, tablet drivers are not present in windows, during first connect, one of device that Windows detect, is linux virtual CD and that partition includes that instalation file. And, sure, I have just written - do not plug tablet as a step b). Well, well, connect tablet to some another PC, just to download that instalation file and continue (drivers) in another PC with rooting, where LenovoUSB drivers should be installed

d) install Google ADB drivers, as mentioned in this post.

e) now, you can connect tablet to PC. Tablet should ask you how to connect USB (MTP, PTP, just charging).

f) if you followed these steps exactlty, no "USB debug authorization" message popup. Its because adb daemon (a SW, ju installed to PC) is not running.

g) Win+R, cmd, cd c:\adb, type "adb devices"

h) now, commandline inform you, adb daemon is starting and thats the moment, tablet asks you for USB debuging authorization.

i) to doublecheck - after first command adb devices, you should see "unauthorized", because this comes before you allowed it in tablet. If you run adb devices once again, you should see "device" instead of unauthorized, thats confirming, you can proceed.

j) so far so good, this is how it behave during first connection, but during the step 17, it differs

k) when you repeat those steps 1-3+9 for the second time, you PC have adb daemon running now. And in this stage, you can force tablet to display that USB debuging dialog by changing MTP to PTP, when tablet asked you so.

I know, this is quite very detailed explanation and for those, who can manage these drivers easy, this is invisible, but once again - it you are not 100% sure, just follow these steps.

10. Now, you are ready for more magic, written in original #1 post - open Win command line/console, by Win+R, cmd, enter.

11. Navigate to installation directory of ADB by "cd c:\adb"

12. as #1 post> type in "adb reboot bootloader", tablet reboot with reporting "FASTBOOT mode...." on screen

13. now, type in fastboot oem unlock and watch the tablet. It will ask for Volume Up to confirm

14. reboot (e.g. by poweroff button or by command adb reboot)

15. Wipe process starts, let it do all the common things like enter gmail account, etc....

16. Now, tablet is in original state, just with one difference / opened bootloader (or whatever exactly it mean), lets continue

17. Now, repeat steps number 1-3+9 (Oem unlocking already enabled) - enable developer options, allow USB debugging, again connect to PC, change to PTP and check Always allow+OK. (See red Edit between 9. and 10.)

18. Back to the original #1 post - Win+R, cmd, enter, cd c:\adb, adb reboot bootloader, message appear on tablet.

19. Omnit original "unlock" command and continue with "fastboot boot TWRP_3.0.2_Lenovo_TB3-730X_Android-6.0_recovery.img"

20. It takes 20-30 seconds, logo appear and later, that point somebody maybe act too fast with the swipe bar. IMPORTANT:

Do not swipe

, just tap the button "Keep read only"

21. In the menu, click Install

22. Navigate to external sdcard and select that SuperSU zip file (step 0) to install and run it without another changes or just select Reboot after finished.

23. Done! Tablet reboot and SuperSu is present

I am sure, 0xAF can find better/faster solution (faster step 15), but these steps worked for me, with Win7 32bit, TB3-730X, firmware 37 and 2.79 supersu.

Good luck

Workaround info/tips:

a) If you are avarage user without skills to install drivers and simply not sure, you done it sucessfully, simply between steps 11 and 12, type in "adb devices", it should report some long nasty (serial) number of connected devices and it indicates you have has succ. done steps to install driver and ADB software.

b) just a recommendation - I have had problems in past, with such steps in S4mini phone just because, I previously test anything (APK, other software and scripts) / KingRoot, KingoRoot, iRoot, mwr, etc... far more later, I found, that process, which worked for many people before and not working for me, it failed because of presense of the similar conflicting tools/SW. This Lenovo Tab3 7 steps.... include factory reset, so think about that / you have to backup all your data before it, thats sure. So, my recommend> If you are not sure, prepare tablet in most default state before start this - do the factory reset/wipe before. Its just one more step, but preventing some unwanted conflicts...

c) after new run, with newly flashed/installed supersu, everybody is impatient to test it asap. It can happend, you saw some errors like Goople play service stop working. Also, you will probably try to install Root checker asap and downloading process will stuck. Do not panic, after new run of Android, GooglePlay service itself is updating and it does not mean, something has been done wrong during the rooting process, just wait and reboot one more time.