[Transformer TF300T General] cmendonc2:
This Optimized Guide is for NvFlash Flatline only! That is for stock Android Versions: 10.6.1.15.3 - 10.6.1.27.5.

According to this post and this post, it works with the tf300tg as well. Bootloader: 10.6.2.11

Original Thread: http://xdaforums.com/showthread.php?t=2455922

Why install NvFlash?

You will need ADB and fastboot for this: http://xdaforums.com/showthread.php?p=42407269. I would suggest keeping the tablet at least at 50% battery.

Guide:

1) Download files

NvFlash for windows.

and the TF300 image, which is a custom recovery for the purpose of flashing the AndroidRoot Bootloader.

Place image in ADB folder, and rename it to: flatline_device.img

2) Install Naked Drivers. This may be optional for you. If you can proceed to the next step without, you won't need it.

3) Enter fastboot by rebooting and holding down the power and vol down button. TF300 enters fastboot automatically since this is 4.2 BL.

4) Next we need to enter a command. In side the ADB folder, hold shift and right click. Then select Open command window here.

first check to make sure the device is connected:

fastboot devices

The device serial number should be listed.

enter command:

fastboot flash recovery flatline_device.img -i 0x0b05

Blue bar on device will fill. Be patient.

5) Reboot the Device back into Android. This is an important step.

6) Reboot into recovery which should be CWM at this point. Go Advanced -> Wheelie. Accept the warning.

step 1) Flash AndroidRoot BL

The device will shut down, reboot into Android. Then reboot back into recovery.

step 2) Once back in recovery select go to Advanced ->:”Generate wheelie blobs” Be patient here too.

They can be found in the device at /data/media/AndroidRoot" or /tmp/AndroidRoot

You can use ADB to get them:

adb pull /data/media/AndroidRoot

or

adb pull /tmp/AndroidRoot

Alternatively, you can use a root file explorer such as ES File Manager. Be sure to copy all of the files out of the directory. Make sure you have root access before you try to search for the files.

Keep this file safe in multiple places.

7)The next section (Accessing NVFlash) is for creating more essential backups with NVFlash.

step 1) Hold down the volume up key while rebooting and the tablet is plugged in via USB. (This may take a few tries to get into APX mode). If you are successful, the screen will be blank and the device name on the computer will be something along the lines of "NVIDIA APX"

step 2) Take the NvFlash tools zip and extract them to a folder. Shift right click in that folder and select "Open Command window here".

step 3) Copy the blob.bin from the Step # 7 above into the NvFlash folder.

step 4) run the command:

wheelie --blob blob.bin

8) Next we run some commands to get even more backup files. These should all be run from the same command window in the previous step.

nvflash --resume --rawdeviceread 0 2944 bricksafe.img

nvflash --resume --read 14 factory-config.img

nvflash --resume --read 7 unlock-token.img

These files will be stored in C:\User\AppData\Local\VirtualStore (on the computer)

If they are not there, run a search on your computer for

*img

9.) Flash any other recovery you want, including TWRP. Be sure it is the correct version for your bootloader.

10.) Store ALL of the img files AND the blob.bin AND all other files in the folder in multiple safe places (email, dropbox, HDD, flash drive, SD card, tape backup, or your favorite plant etc.)

11.) Enjoy the peace of mind that you can now restore your device if you brick it :)

Hit that thanks button if I helped and also thanks to [MENTION=3421937]bucket81[/MENTION] and of course AndroidRoot.mobi devs [MENTION=962182]rayman[/MENTION]