Introduction

In this tutorial I am going to show you how to root your Asus Transformer TF101 or Asus Transformer Prime TF201, running the latest version of Ice Cream Sandwich (ICS), which at the time of writing is 9.2.1.21 for the TF101 and 9.4.2.21 for the Prime TF201. The only way to root your tablet running 9.2.1.21 or 9.4.2.21 WITHOUT unlocking your bootloader, is to downgrade to an older firmware version, get root, upgrade back to the latest firmware version available and restore our root access using OTA Root Keeper.

The benefit of this method is that you will not void your warranty, as your bootloader will remain locked. This whole process will take about 30 minutes to complete and will keep your data intact. I created this tutorial all by myself after I successfully rooted my Transformer Prime TF201 running 9.4.2.21 and a Transformer TF101 of a friend of mine running 9.2.1.21.

Disclaimer

Rooting (and downgrading) is a complicated process. I’ve tried to make this tutorial as easy to follow as possible. It contains lots of screenshots, which are in Dutch (Nederlands) by the way, but I also assume you have basic computer knowledge. If you don’t even know what ‘rooting’ is, then this is not for you!

In this tutorial I will be rooting my Transformer Prime TF201, but the process for the Transformer TF101 is exactly the same. Just make sure you don’t mix up the firmware numbers.

I also would like to point out that I am not responsible for any possible damage that this process may cause to your tablet. Downgrading and rooting Android devices is highly experimental and may turn your device into worthless brick. Proceed at your own risk!!

Last but not least: English is not my first language, so please excuse any spelling errors I’ve made below.

Checklist

-Make sure your Transformer is FULLY Charged

-Make sure your Transformer is NOT Docked

-Make sure your Transformer’s bootloader is LOCKED, i.e. you are NOT running a custom ROM or have ClockworkMod flashed.

-Make sure your firmware build number is equal to 9.2.1.21 if you have a Transformer TF101 or 9.4.2.21 if you have a Transformer Prime TF201

-Only use the ORIGINAL USB Cable, WITHOUT any USB extension cables

-Take your time, don’t rush things and be patient.

-Follow the instructions precisely and all will be OK!

Preparation: Backup Apps&Data

Let’s start by making a backup of our apps and data in case something goes wrong. Open up the Asus Back-up app.



Accept the Terms of Agreement and click on ‘Start’.



In the right upper corner select ‘Data & Application’ as ‘Back-uptype’, click ‘Select all’ and click ‘Back-up’. The time it takes before the backup finishes depends on the amount of apps you have installed on your tablet. Just be patient.



Preparation: Download & Copy older firmware

Before we continue, we need to verify which exact firmware version our Transformer tablet is running. To do so go into ‘Settings’ –> ‘About Tablet’ and scroll down until the ‘Build- number’ appears, like so:



As you can see, my tablet is running the latest version of ICS available, which at the time of writing is 9.4.2.21 for the Prime TF201. But also note the ‘WW’ in front of the number, which means ‘WorldWide’. This is important because Asus releases different types of firmware versions for different countries. For example, Transformer tablets in the USA will have an ‘US’ prefix instead of the ‘WW’ prefix. When downgrading (or flashing a new ROM onto) your tablet, it is very important to make sure you have the correct corresponding firmware type. In other words: Do NOT flash a ‘US’ type firmware on your tablet if it originally was a ‘WW’ type tablet. This WILL cause problems!

Now that we know which firmware type our tablet has, in my case that’s ‘WW’, we need to download an older firmware for our tablet to be able to gain root access. This is needed because the latest firmware version we’re running (9.4.2.21) does not contain any exploits that we can use to gain root access directly. This is because Asus patches those exploits with every firmware update they release. However, older firmware versions do contain exploits to gain root access and thus we need to downgrade to one of those older firmware versions first before we can gain root access.

If you have an Transformer TF101, I recommend downloading firmware version 9.2.1.11, which can be found here:

WW version: https://freek.ws/transformer/TF101/WW_epad-user-9.2.1.11.zip

US version: https://freek.ws/transformer/TF101/US_epad-user-9.2.1.11.zip

Again, make sure to download the correct corresponding firmware type for your tablet, as explained above!

If you have a Transformer Prime TF201, I recommend downloading firmware version 9.4.2.15, which can be found here:

WW version: https://freek.ws/transformer/TF201_Prime/WW_epad-user-9.4.2.15.zip

US version: https://freek.ws/transformer/TF201_Prime/US_epad-user-9.4.2.15.zip

Again, make sure to download the correct corresponding firmware type for your tablet, as explained above!

After you’ve downloaded the corresponding older firmware version for your tablet, you’ll end up with a .zip file. Unzip the .zip file, which will leave you with a ‘META-INF’ folder and a ‘blob’ file.



You can delete the ‘META-INF’ folder; we only need the ‘blob’ file.

Connect your Transformer tablet to your computer using the original USB cable and copy the ‘blob’ file into the root of the INTERNAL STORAGE of your Tranformer (NOT the SDCard), like so:



Preparation: Change tablet settings

Before we can downgrade our tablet, we need to change some settings in our tablet.

Before you continue, please disconnect the tablet from your computer!

On your tablet, go to Settings –> Developer Options –> Click OK at the message that pops up –> place a checkmark at ‘USB debugging’ –> Click OK at the message that pops up.



Also go to Settings –> Security –> place a check mark at ‘Unknown Sources’ –> Click OK at the message that pops up.



Lastly, go to Settings –> Accounts & Synchronization –> Uncheck (remove) the check mark at ‘Start Asus Sync’.



Download ‘Downgrade Tool’

We now need to download a tool which will downgrade the firmware for us. This tool is no more than an automated version of a downgrade exploit invented by Wolf849 (1) and can be found here:

https://www.freek.ws/downgrade_tool (2)

Once downloaded, you will end up with another .ZIP file. Again unzip this file and you’ll end up with a bunch of files. This .ZIP file also contains the Drivers we need to use in the next step!



Preparation: Install Drivers

Now connect your tablet to your computer again, using the original USB cable.

Windows now probably will l complain a ‘Device driver software was not successfully installed’ in the right bottom corner of your screen.



To solve this, go ‘Start’, right click on ‘Computer’ –> ’Properties’.



In the new screen that pops-up (assuming that you’re running Windows 7) click on ‘Device Manager’, in the left upper corner.



You will now see a device called ‘Asus Android Composite ADB Interface’ listed under ‘Other devices’ with a yellow exclamation mark. Right click on it and select ‘Update driver’.



In the new screen that pops-up, select ‘Browse my computer for driver software’.



In the next screen, browse to the ..\Drivers\Android folder which was included in the .zip file you’ve downloaded above and click ‘Next’.



Your computer should now install the correct drivers for your tablet. If all went well, you should see this screen:



Click ‘Close’ and check if the ‘Asus Android Composite ADB Interface’ is now listed under ‘Asus Android Devices’ instead of ‘Other devices’, like so:



Preparation: Kill unwanted apps

Before we can downgrade, we need to make sure the apps ‘Asus Sync’ and ‘Splashtop Remote’ are not running.

To do so (do NOT disconnect your tablet from your computer!) on your tablet go to Settings –> Apps –> All –> Search for ‘com.asus.pcsynclauncher’ and ‘Splashtop Remote’.





Make sure to ‘Force stop’ both apps. To do so, click on them and press ‘Force stop’.





After Force stopping, the ‘force stop’ button will be greyed out which means the app is no longer running in the background.





Downgrading

We are now finally ready to downgrade our tablet. Open (by double clicking) ‘viperMOD Primer Tool v4.5 – Modded by bpear_v3.exe’ . You will see this screen:



We need option 1, so press 1 on your keyboard and hit the Enter button to continue.

NOTE: Although it says ‘Downgrade unrooted US Prime to .15’, this also works for WW Prime and also for US and WW TFT101. Don’t worry :)

You’ll get this screen:



Hit the Enter button to continue.

You’ll get this screen:



Once again, hit the Enter button to continue.

The downgrade process will now begin. DO NOT DISCONNECT YOUR TABLET FROM YOUR COMPUTER DURING THIS PROCESS! Disconnecting your tablet during the downgrade or rooting process can break your tablet and turn it into a unless (but very expensive) brick!

If all goes according to plan your tablet will reboot first, then the older firmware we’ve copied earlier (the ‘blob’ file) will be copied to the correct system folders (this can take up to 10 minutes, BE PATIENT!!) and then your tablet will reboot once again running the older firmware. While rebooting, the tablet will stop for a while displaying the Asus EEE Logo with a progress bar; Don’t worry – the bar will move in 1 minute or so. Just be patient!

If the downgrading process has finished, you’ll see this screen:



Hit the Enter button, followed by pressing 8 and hitting the Enter button to exit.



To verify if your tablet has indeed been downgraded successfully, go into Settings à About tablet and verify the ‘Build-number’. It should say ‘9.2.1.11’ if you have a Transformer TF101 or ‘9.4.2.15’ if you have a Transformer Prime TF201, like so:



If that’s the case, we can proceed by rooting our tablet. If not, then you’ve done something wrong. Please start from the beginning and make sure you exactly follow each and every step precisely.

Download ‘Rooting Tool’

To root our tablet, we need to download another tool, which can be found here:

https://www.freek.ws/rooting_tool (3)

You’ll end up with another .zip file. Again unzip this .zip file somewhere and you’ll end up again with a bunch of files and folders.



Before we can root our tablet, we need to make sure again that the apps ‘Asus Sync’ and ‘Splashtop Remote’ are NOT running. Please see above on how to do this.

Rooting

We now can finally root our tablet. Open (by double clicking) ‘viperMOD PrimeTime v4.5.exe’ . You will see this screen:



We need option 1, so press 1 on your keyboard and hit the Enter button to continue.

NOTE: Although it says ‘Root (only method for Prime on ICS v9.x.x.11)’, this also works for the Asus Transformer TF101 running 9.2.1.11 and Transformer Prime TF201 running 9.4.2.15. Don’t worry :)

However, whatever you do, do NOT flash recovery if you’re NOT on a Prime. That option is ONLY for Prime TF201!!

Let’s continue. You’ll now get this screen:



Hit the Enter button to continue.

You’ll get this screen:



Once again, hit the Enter button to continue.

The rooting process will now begin. Once again, DO NOT DISCONNECT YOUR TABLET FROM YOUR COMPUTER DURING THIS PROCESS!



If all goes according to plan some files will be transferred to your tablet first, the exploit will be used to gain root access and BusyBox will be installed. Finally your tablet will reboo and once rebooted it will be rooted! If the rooting process has finished, you’ll see this screen:



Hit the Enter button, followed by pressing 7 and hitting the Enter button to exit.



Protect Root with OTA RootKeeper

To verify that your tablet has indeed been rooted, go into the market, download ‘OTA RootKeeper’ and open it.



On opening, a SuperUser prompt will popup asking if ‘OTA RootKeeper’ is allowed to get root permissions. Hit ‘Allow’



If correctly, OTA RootKeeper will confirm that your device is rooted:



Now before we continue, it is important that we protect our root access. Like I said before, with every new firmware update Asus releases, they patch any exploits which will gain us root access. So to make sure we can safely upgrade to a newer firmware version (in our case 9.2.1.21 or 9.4.2.21), we need to protect our root access BEFORE upgrading. If you don’t do this, you will lose your root access and you can start all over again. I hope you understand the importance of this app, so whatever you do, DO NOT UNINSTALL OTA ROOTKEEPER!

To protect your root access, press the ‘Protect root’ button in OTA RootKeeper. It’ll take just a few seconds. Once it has finished protecting our root access, you should see this:



Upgrade to latest firmware

Now we’re ready to upgrade back to the latest firmware available, in our case 9.2.1.21 for the TF101 or 9.4.2.21 for the Prime TF201

To do so, on your tablet, go to ‘Settings’ –> ‘About tablet’ –> ‘Update systemfirmware’. It should now say a new update is available and start downloading it. If it doesn’t say there’s an update available, just wait a couple of hours and try again. It should show up eventually. If still doesn’t show up after 24 hours, make sure you flashed the correct version of firmware (ie. WW if your tablet is a WW version).

You can check the download progress in the notification area, in the right down corner of your tablet. If it has finished downloading, a notification will be placed in the notification area, in the right down corner of your tablet. Click on it and this screen will appear:



Now hit Install and your tablet will upgrade to the latest firmware as it normally would do.

Restore Root using OTA RootKeeper

Finally, once the upgrade has finished, open OTA RootKeeper and restore your root access.



Done!

Congratulations! You’ve now successfully rooted your Transformer TF101 or Transformer Prime TF201 tablet, running the latest available firmware (9.2.1.21 or 9.4.2.21)! That wasn’t so hard, was it ;) ?

Credits & Thanks to:

(1) Wolf849 @ xda-developers for inventing a downgrade method for Transformers running 9.2.1.21 or 9.4.2.21

http://forum.xda-developers.com/showthread.php?t=1622628

(2) bpear96 @ xda-developers for creating an automated downgrade script, based upon –Viperboy-‘s tool using Wolf849’s downgrade method.

http://forum.xda-developers.com/showpost.php?p=25511847&postcount=100

(3) -Viperboy- @ xda-developers for creating his ‘viperMOD PrimeTime’ tool to automatically root a Transformer tablet.

http://forum.xda-developers.com/showthread.php?t=1427125