[Transformer TF300T General] xaueious:
I have a Canadian ASUS TF300 purchased from Futureshop. It shipped with WW firmware, and I updated OTA to WW9.4.3.30 before starting this.

I have lost root in the process. But I wasn't keep on keeping it in the first place. I kept all my apps and am now on US10.4.2.9 Jellybean Android 4.1.1. Maybe someone can chip in on how to keep root.

My device is NOT unlocked. Following this procedure requires that you root your device temporarily.

You will end up with JB with one modified binary (su, but with safe system permissions as a result of the rooting process).

This method is very time consuming (1-2 hours), so I don't recommend it for everyone. You need knowledge of ADB to proceed with this.

How To Flash (Unlocked/locked Device)

1) Convert to US9.4.3.30 using the blob:

Download US9.4.3.30 from the ASUS download page here: http://support.asus.com/Download.aspx?SLanguage=en&m=ASUS+Transformer+Pad+TF300T

Open the firmware download package with 7zip or similar, and extract 'blob'.

2) Copy blob into your internal memory (/sdcard/). I used adb push to do this

3) Continue following 'Method 2' from here: http://xdaforums.com/showthread.php?t=1622628

(You probably want to clean up the symlink after you finish this method)

You are now on the stock US9.4.3.30 firmware

4) Perform the official upgrade to the US10.4.2.9 firmware manually

Download US10.4.2.9 from Asus: http://www.asus.com/Tablet/Transformer_Pad/ASUS_Transformer_Pad_TF300T/#download

Remove any external storage media attached to the device before proceeding.

The downloaded file is to be placed in the root directory of the internal storage (/sdcard). Reboot to install if the prompt to install doesn't come up right away.

(instructions by Bolandk. not tested by me.)

FROM THIS POINT FORWARD, THE INSTRUCTIONS BELOW ARE OBSOLETE AND ARE KEPT HERE FOR FUTURE REFERENCE ONLY

4) Root the firmware using the DebugFS method: http://xdaforums.com/showthread.php?t=1706588

IF YOU WANT TO KEEP ROOT, FOLLOW THIS: http://xdaforums.com/showthread.php?t=1840504

5) Use this method to force the FOTA update (dlpkgfile)

Download dlpkgfile from this thread:

http://xdaforums.com/showthread.php?t=1840397

Follow this: http://xdaforums.com/showthread.php?t=1803090

The difference is that our device does not vibrate. You want to hit 'vol up' right when your device shows any text, and this is within 5 seconds of you pressing the voldown+power combination. If you miss this, you need to recopy 'command' back into /cache/recovery.

6) The update process will start automatically. This takes 20 minutes to complete.

Region conversion instructions

Since ASUS has posted the Jellybean updates for a while now, I thought I'd update this post with instructions to change to another region.

To region convert, you need to download the firmware for the target region. Ideally you want the version you are currently on. I think you may end up losing root in the process, but I don't know a way around that at the moment.

You do not have to be bootloader unlocked to do this.

Extract the xxxUpdateLauncher.zip into the root directory of a microSD card formatted to FAT/FAT32. Then rename the file as EP201_768_SDUPDATE.zip. Reboot into the bootloader (vol - and power), and select the first option (left most square) when the menu comes up. The firmware update will start automatically in this mode.

I converted back from a US to a WW build without wiping using this method.