[Asus Transformer TF700] MysticMgcn:
You can revert to the ICS bootloader with the .30 firmware following instructions below only using .30 firmware instead of the JB Firmware.

Thanks goes to saltxyz for this find.

I think we've taken this thread about as far as it can go information wise. Please join me in my new thread here: http://xdaforums.com/showthread.php?t=1886877

Thank you everyone for taking the plunge with me, the Thanks, guidance, and making this a newsworthy thread!

You can download my custom kernel here or below: https://www.dropbox.com/sh/ay9iolwcfbxu0wm/_vpRpSQ6nK/kernel.zip

STOP

1. I am not responsible for any issues this may cause your device and won't be held for any soft-bricks, hard-bricks, boot loops, exploding pets or Resonance Cascades.

2. Go ahead and download ADB/Fastboot to make your life easier: http://developer.android.com/sdk/index.html

What Works/Doesn't Work

What Works:

Almost everything!

What Doesn't Work:

Changing Brightness Settings without the use of a Third-Party App

Resolution (DPI is set to 160 by default and changing it through an App or directly with build.prop makes no changes) - FIXED

You WILL lose Root and Custom Recovery with these methods

Drivers

I used the ASUS Android USB Drivers from the following post for ABD/Fastboot: http://xdaforums.com/showthread.php?t=1706588

Installation

Method 1 for Locked/Unlocked Bootloader with Stock Recovery and/or Root

1. Power off your tablet

2. Download the latest TF300T firmware (XX_epaduser_10_4_2_9_UpdateLauncher.zip) from Asus site based on your SKU location (eg. ww, US, etc): http://support.asus.com/Download.aspx?SLanguage=en&m=ASUS Transformer Pad TF300T&p=20&s=16

3. Right click and extract the downloaded .ZIP file (XX_epaduser_10_4_2_9_UpdateLauncher.zip) onto your desktop

4. Rename the extracted .ZIP to "EP201_768_SDUPDATE" (without the " ") and copy it to your MicroSD card

5. Insert the MicroSD card in your tablet

6. Boot your tablet into Recovery by pressing and holding Volume Down AND Power for 5 seconds

7. A message will inform you that you have 5 seconds to enter Recovery; press Volume Up before the 5 seconds expire

8. At this point the device will go in recovery and should start updating your firmware

Method 2 for Unlocked Bootloader with Custom Recovery and/or Root

1. Power off your tablet

2. Download the latest TF300T firmware (XX_epaduser_10_4_2_9_UpdateLauncher.zip) from Asus site based on your SKU location (eg. ww, US, etc): http://support.asus.com/Download.aspx?SLanguage=en&m=ASUS Transformer Pad TF300T&p=20&s=16

3. Right click and extract the downloaded .ZIP file (XX_epaduser_10_4_2_9_UpdateLauncher.zip) onto your desktop

4. Copy the extracted .ZIP (XX_epad-user-10.4.2.9.zip) to your MicroSD card

5. Insert the MicroSD card in your tablet

6. Boot your tablet into Recovery by pressing and holding Volume Down AND Power for 5 seconds

7. A message will inform you that you have 5 seconds to enter Recovery; press Volume Up before the 5 seconds expire

8. From your recovery menu press Install and select the .ZIP file (XX_epad-user-10.4.2.9.zip)

9. Wait until the install process ends and then restart your device

Method 3 Advanced using Fastboot

1. Power off your tablet

2. Download the latest TF300T firmware (XX_epaduser_10_4_2_9_UpdateLauncher.zip) from Asus site based on your SKU location (eg. ww, US, etc): http://support.asus.com/Download.aspx?SLanguage=en&m=ASUS Transformer Pad TF300T&p=20&s=16

3. Right click and extract the downloaded .ZIP file (XX_epaduser_10_4_2_9_UpdateLauncher.zip) onto your desktop

4. Right click and extract the new .ZIP file (XX_epad-user-10.4.2.9.zip) onto your desktop; you should now have the blob binary and META-INF folder on your desktop

5. Copy the blob binary to your platform-tools folder (C:\Program Files\Android\android-sdk\platform-tools or C:\Program Files (x86)\Android\android-sdk\platform-tools)

6. Plug tablet into your computer

7. Boot your tablet into Fastboot by pressing and holding Volume Down AND Power for 5 seconds

8. A message will inform you that you have 5 seconds to enter Recovery; press Volume Down twice to select Fastboot and then Volume Up before the 5 seconds expire

9. Open a command prompt and cd into your platform-tools folder; or press right-Shift on your keyboard and right-click the platform-tools folder and click "Open command window here"

10. Enter the following command in the command prompt: "fastboot -i 0x0B05 flash system blob" (without the " ")

11. Once the previous command completes enter: "fastboot -i 0x0B05 reboot" (without the " ")

RECOMMENDED but Optional Steps:

If you are using Stock Recovery it is advised to Factory Data Reset or Wipe Data both BEFORE and AFTER the Firmware Upgrade

If you are using Custom Recovery it is advised to wipe ALL partitions

Unlocking the Bootloader

You can use the ASUS Unlock Tool from the ASUS Support site to unlock your bootloader. Despite ASUS saying it's for ICS it works fine on JB. Detailed instructions to come.

Recovery (TWRP) **Requires Unlocked Bootloader**

1. Turn your tablet off

2. Download the latest TWRP blob: http://teamw.in/project/twrp2/105

3. Rename the blob binary (openrecovery-twrp-X.X.X.X-tf700t.blob) to "twrp.blob" (without the " ")

4. Copy the twrp.blob binary to your platform-tools folder (C:\Program Files\Android\android-sdk\platform-tools or C:\Program Files (x86)\Android\android-sdk\platform-tools)

5. Plug tablet into your computer

6. Boot your tablet into Fastboot by pressing and holding Volume Down AND Power for 5 seconds

7. A message will inform you that you have 5 seconds to enter Recovery; press Volume Down twice to select Fastboot and then Volume Up before the 5 seconds expire

8. Open a command prompt and cd into your platform-tools folder; or press right-Shift on your keyboard and right-click the platform-tools folder and click "Open command window here"

9. Enter the following command in the command prompt: "fastboot -i 0x0B05 flash recovery twrp.blob" (without the " ")

10. Once the previous command completes enter: "fastboot -i 0x0B05 reboot" (without the " ")

Root **Requires Unlocked Bootloader AND Custom Recovery**

1. Download the latest Custom Recovery installable SuperSU .ZIP (CWM-SuperSU-vX.XX.zip): http://xdaforums.com/showthread.php?t=1538053

2. Plug tablet into your computer

3. Copy the SuperSU .ZIP (CWM-SuperSU-vX.XX.zip) to Internal Storage

4. Turn your tablet off

5. Boot your tablet into Recovery by pressing and holding Volume Down AND Power for 5 seconds

6. A message will inform you that you have 5 seconds to enter Recovery; press Volume Up before the 5 seconds expire

7. From your recovery menu press Install and select the SuperSU .ZIP (CWM-SuperSU-vX.XX.zip)

8. Wait until the install process ends and then restart your device

9. Now your tablet should be rooted