[T-Mobile, Samsung Galaxy SIII] mnasledov:
UPDATED 2013/11/21: Added more warnings.

This is for US SGH-T999 devices ONLY. If there is ANY letter after your model such as 'L' or 'V' DO NOT FLASH THIS OR YOU WILL DEFINITELY BRICK YOUR PHONE! For SGH-T999

V

VLDLD1 firmware, please see this thread: http://xdaforums.com/showthread.php?p=41701398

DO NOT flash this if you are running latest 4.3 (*MJC) firmware. It WILL brick your device. Currently there is NO way to downgrade from MJC firmware without a brick due to the Knox security stuff added to that firmware release.

Currently I don't have a SGH-T999L firmware update script, sorry. If someone would like to work with me on guinea pigging it and has heimdall installed, PM me and we'll get it done in no time.

This is the latest firmware update for US T-Mobile (SGH-T999) that flashes the UVDMD5 radio and bootloader with a convenient update.zip. Flashing it on anything other than the US SGH-T999 is strongly not advisable. It will likely brick your phone. It CANNOT be used on the Canadian T999V variant.

This script flashes all of the firmware that comes with the UVDMD5 OTA -- this upgrades the firmware as if you had just flashed the whole package through Odin, but without actually touching system, recovery, kernel, etc. There are two versions of the script -- one just does the bootloader+firmware, the other does bootloader+firmware+modem.

What are these firmware files?

rpm.mbn - Resources and Power Manager

sbl2.mbn - Part of Secondary Bootloader

sbl3.mbn - Part of Secondary Bootloader

aboot.mbn - AP Bootloader

tz.mbn - Trust Zone

NON-HLOS.bin - Modem / Radio

Why do I want this?

If your phone has old enough firmware, newer CM10.1 builds will no longer install on it. It is unknown if updating to UVDMD5 from UVDLJC, for example, has any noticeable positive effects. No known negative effects have been reported and the Odin method ends up upgrading all this stuff anyway.

Note that you can flash the above files via heimdall but this updater below is handy as you don't need heimdall, download mode, etc. All you really have to do is flash it in recovery.

Flashable UVDMD5 Bootloader / Firmware / Modem update.zip: https://dl.dropboxusercontent.com/u/173554095/T999 Devel/T999_UVDMD5_firmware_v4.zip (md5: d040ea4193234cbe9a36f95ffa780086)

Above flashable update without modem: https://dl.dropboxusercontent.com/u/173554095/T999 Devel/T999_UVDMD5_noradio_v4.zip (md5: 4c4aa065ee7c86dccea92ec7856a7af4)

OLDER UVDLJC Firmware update.zip script (w/modem) -- only if you specifically need it for some reason.: https://dl.dropboxusercontent.com/u/173554095/T999 Devel/T999UVDLJC_firmware.zip (md5: 537b69ec54ce6a3580a9c56ca379e72c)

Instructions:

(1) Put this .zip file on the root of your sdcard.

(2) Reboot to recovery

(3) Choose .zip file from sdcard and select this file and flash it.

(4) Reboot and you're done. I didn't find any wiping of any kind necessary.

NOTE: If you plan to flash anything else, please at least reboot recovery or it won't pick up the bootloader change.

Changes:

v1: Initial release. Modified someone's UVDLJC firmware update.zip script to update to UVDMD5.

v2: Removed certs from a previous update.zip that could've been causing signature verification errors with some recoveries.

v3: Updated Edify script courtesy of [MENTION=4788211]Aerowinder[/MENTION]

v4: Corrected a derp in package_extract_dir() (my fault) that prevented v3 from working at all. I've since tested v4 personally and verified it.

Many thanks to whomever put together the original update.zip and to Khaytsus and invisiblek for pointing me in the right direction. Also many thanks to all who've tested it and provided feedback. There is no greater enjoyment than in helping people.

I've also hacked together a firmware backup script that works for both T999 and T999V: http://xdaforums.com/showthread.php?p=41548550

DISCLAIMER: I do not take any credit for this stuff, I just put it together. I am not liable for your device if you break it, etc etc. READ THE WARNINGS BEFORE PROCEEDING.