[Galaxy Tab  Android Development] Chainfire:
DO NOT USE THIS ON THE GINGERBREAD RELEASES ! THE SAMSUNG GINGERBREAD RELEASES DO HAVE SIGNED BOOTLOADERS, BUT THEY ARE NOT LOCKED. In other words, you can still flash custom kernels and such, and the bootloader patch will only break things, not fix them.

To read the history of this problem, see the 2nd post of this thread (scroll down).

A number of new firmwares for the Samsung Galaxy Tab come with "signed / protected" bootloaders. These new bootloaders prevent you from flashing custom or otherwise unsigned kernels on the device. Trying to do so anyway will result in errors and usually requires you to reflash your ROM completely.

I hope everybody here has learned the lesson not to just flash anything that SamFirmware releases ;)

The patch

After a great many hours of researching, testing and coding, myself (Chainfire) and Rotohammer have come up with a patch that works on most devices (currently all known GSM Tab variants), and flashes back unprotected JJ4 (T-Mobile ?) bootloaders, or the original P1000N bootloaders for the Latin models. The app only patches when it finds protected bootloaders, and you have to press a button for that, so the app can also be used to look at your current status.

The patch has been tested repeatedly and with success on (0 bricks so far):

- GT-P1000 Euro/International/Unbranded Galaxy Tab

- SGH-I987 AT&T Galaxy Tab

- SGH-I987 Rogers Galaxy Tab

- SGH-T849 T-Mobile Galaxy Tab

- GT-P1000L Latin Galaxy Tab (use LATIN version!)

- GT-P1000N Latin Galaxy Tab (use LATIN version!)

Additional thanks to: koush, neldar, richardtrip, AColwill, farahbolsey, deezid, wgery, tmaurice, rmanaudio, crisvillani, alterbridge86, ivannw, themartinohana, luisfer691 (in no particular order!)

Please note that even though there have not been any bricks so far, replacing bootloaders is a very dangerous operation that may BRICK your device, and you should think twice before using the patch. Using the patch is completely AT YOUR OWN RISK!

Instructions

Download the attached APK, install it on your device, and run it. It will show you a status screen, and if your device is compatible and you have protected bootloaders, the bottom entry "Patch bootloaders" will become available. Tapping it will start the patch procedure.

Note that the patch requires root !

Mini-FAQ

--- After the fix, my "zImage" still shows signed ! Is this a problem ?

No, this is perfectly fine! What matters is that "PBL", "SBL" and "SBL_Backup" are not signed. If "zImage" is signed, it means this ROM can be flashed onto a device that has signed bootloaders. UNsigned "zImage"s can NOT be flashed on signed bootloaders. This is the origin of the problem, because custom kernels are always UNsigned "zImage"s !

--- Can I now flash any ROM and just use this application to fix the bootloaders ?

Technically yes. But it would be stupid to do so. Flashing bootloaders (what this app does) is VERY dangerous, it is the only way to really brick a Tab. If you want to flash a new ROM, make sure it DOES NOT contain bootloaders. Remove them yourself, or wait for somebody else (like Rotohammer) to remove the bootloaders and post the "safe" ROM. Even though this patch is available, if at all possible, you should always try to avoid having to use it.

CDMA tabs

There is currently no support for CDMA Galaxy Tabs, nor do we know if support is needed at this time.

LINKING

You are expressly forbidden to repost the APK elsewhere. If you post about this, post a link to this thread, not to the download (or a repost of the download).

Download

Don't forget to donate and/or press the thanks button!

For non-XDA members who cannot access the attachment, here are multiupload links:

Euro / International / Unbranded / AT&T / Rogers / T-Mo: http://www.multiupload.com/EMOCU1S0V2

Latin (P1000L and P1000N): http://www.multiupload.com/3TJ3YWMWJR

MAKE SURE TO SELECT THE RIGHT DOWNLOAD!