Originally Posted by pruano

Then you must have, at some point, flashed a modem firmware from another device; why it worked before, its most likely due to a custom ROM you had installed and stopped working with the stock versions.

Just for the record, did you follow this procedure to gain root back?

Strange... I never flash with another ROM.
Only stock ROM 3.2.1 recently.
But I think I've make a big mistake when I had play with Titanium Backup and delete very important drivers.

No, I only use Odin for flashed ROM (if I understand what you say).
Odin don't work for root.
I follow the 'command' procedure with fastboot.

I don't have time now but I promise coming back for explain how I've flash a ClockWork Mod Recovery (6.x.x.x) with a stock ROM (usually, the original recovery coming back after each reboot, but now, I've the CWM recovery )

Ok, I will try to explain with my bad english.
I already say, I never flash a custom ROM on this tab.
Only flash to 3.2.1 follow of automatic upgrade to 4.0.4 via OTA.

After, the tab stay unlock but no root.
We must make a new root ant implant a CWM.
But the problem with this tab is : if you get a CWM with fastboot (dont work with ODIN with my tab), after each reboot, the stock ROM erase CWM and reload the original recovery.
This original recovery is very poor (not BackUp/Restore, not USB mode, ...).

You must follow this thread : http://forum.xda-developers.com/show....php?t=1079781 for root.
After the root, verify if your tab is really root because, many device show the icon root but don't rooted ! (for ex. install Titanium Backup ans launch it)
If you have an error message, your tab is not really root then you must download this file : Superuser-3.1.3-arm-signed.zip (source : http://androidsu.com/superuser/) and copy the file to your SDcard (tab memory) in the first level.
Launch de CWM with Fastboot, and Install ZIP from SD (ZIP = Superuser-3.1.3-arm-signed.zip).
Now, your tab is really rooted.

Now, you don't have yet the Recovery ClockWorkMod 6.0.
You can get it here : http://droidbasement.com/galaxy/roms...covery.tar.md5

Open 'recovery.tar.md5' with Winrar (or other) and extract recovery.img
Copy this file in the same folder with fastboot.exe (on your PC - windows method).


Flashing CWM 6.0.2.7 (part of source : http://forum.xda-developers.com/show....php?t=1079781)

1) Power off your Tab and power it back on, while holding the VOLUME DOWN button.

2) When the DOWNLOAD / FASTBOOT icons appear, press VOLUME DOWN again to select FASTBOOT icon (the one with the USB logo) and press VOLUME UP to confirm selection.

3) Confirm you are now in fastboot mode and do a:

fastboot devices

If all is well, you should see your device serial number.

4) Run the following command:
Temp Root:

fastboot boot recovery.img

..and wait. If your tab reboot to CWM Recovery 6.0.2.7, you win

If OK, reboot your tab and go to step 1), 2), 3) and following 'Permanent Root' here :

5) Permanent Root:

fastboot flash recovery recovery.img

Reboot your tab and return to steps 1), 2), 3), 4)
You're now in the CWM Recovery 6.0.2.7

You must 'Reboot' your tab, but you can read a warning message (up of the screen).
I can't exactly what it say but it's same : "Warning, if you reboot your tab in YES mode, you loose your original bootloader"
You can see a lot of NO and one YES.
If you press NO, you return to original (old) bootloader
If you press YES, you definitly accept de CWM Recovery 6.0.2.7

Done...

Very important : follow steps 1), 2), 3), 4) and if you tab reboot in CWM Recovery 6.0.2.7, it's ok. If not, don't persist in this method.

And you make that on your risk.
But it work for ma tab P7100 10.1v