[Samsung Galaxy Tab A series Guides, News, & Discus] apoorvsxna:
My university in Uttar Pradesh, India has been distributing free tablets (Samsung Galaxy Tab A9) to students. The device itself is decent but there are a lot of background surveillance processes and restrictions on it that nerf the overall performance. You can't even change the wallpaper and Samsung Knox is what enforces this. This guide will allow you to get rid of it.

This procedure will erase all data on your device. You will not be able to receive system software updates after this and you will see a warning every time you restart your tab. However, if you really want to get an update, you can flash the latest firmware and repeat the procedure.

Before you begin, this is what you'll need on your PC:

Odin

Stock Firmware- Download and extract.

Patched boot.tar file for root. I'd suggest patching it yourself using Magisk on android. But if you want to be lazy, I've attached the patched file with this post (firmware version X115XXU2BXE5).

Magisk APK - Download

Termux APK - Download

This guide was somewhat inspired by this original post by Hyperio546. But I believe that method has been patched, or at least it doesn't work on Tab A9.

Guide:

1. Power off the tablet.

2. Enter recovery mode.

3. Select "Reboot to bootloader".

4. Use Odin to flash stock ROM (BL, AP, CP, CSC).

5. Wait for tablet to reboot.

6. Begin setup process and connect to Wi-Fi.

7. Continue setup until reaching the screen shown in the attached picture.

View attachment 6122032

8. At this point, try to force stop the setup and access settings from the quick settings dropdown. (This is a tricky step, I managed to do this by turning off the Wi-Fi router.) In case you aren't able to stop the setup from completing, you'll have to start over.

9. In settings, enable Developer Options by repeatedly tapping the build number.

10. Within Developer Options, enable OEM unlock. If OEM unlock is not present in the developer settings, go back to the above mentioned screen and allow it to continue for a bit and then stop it again (preferably at 50%).

11. Once OEM unlock is enabled, power off the tablet.

12. Disconnect any cables.

13. Open Odin on your PC and connect the cable to the PC.

14. Hold volume up and down buttons simultaneously while connecting the cable to the tablet.

15. From the 3 options shown, hold volume up to unlock the bootloader.

16. Allow the tablet to restart, accepting any prompts.

17. Let the tablet reach the welcome screen, then power off.

18. Again, hold volume up and down while connecting the USB cable. This time, press volume up once to continue.

19. In Odin, select the patched "boot.tar" file (attached) in the AP tab and start the process.

20. When Odin shows "PASS", the tablet will reboot. It is now rooted.

21. If the tablet goes to recovery and reports corrupted system data, select factory reset.

22. The tablet should now boot normally. Set it up and disable Wi-Fi once you reach the home screen.

23. Transfer Magisk and Termux APK files to the tablet.

24. Install Magisk first, then Termux.

25. Open Termux and type

su

. Grant root access when prompted.

26. Enter this command to remove Knox:

pm uninstall --user 0 com.sec.enterprise.knox.cloudmdm.smdms

27. Type "exit" twice to close Termux.

Congratulations. The tablet is now yours!