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[GUIDE][13/11]Update/Recovery/Root/Downgrade Android 4.2.1 on Unlocked/Locked Devices

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Asus released the new Android 4.2 to our beloved devices and you may be wondering how can you update if you are unlocked and how can you root it.



Note: this guide was updated with the 2.5.0.0 TWRP. For this to work properly, you will need to use the last 10.6.1.27.1 version of the tablet, or a newer one. If you are already on a previous 4.2.1 version, please update to the new one using this same guide. If you flash this recovery with the older versions of the 4.2.1 bootloaders, you will end up with a double screen! New TWRP versions won't be able to mount boot and recovery, and won't work with all SD cards, not to talk about backup issues!



Things you should know before you start:

- I marked each title of this guide with [LOCKED BL], [UNLOCKED BL] and [BOTH BL] to specify witch ones will work with locked/unlocked or both bootloaders, respectively.
- Please verify if you have the correct drivers for the tablet installed on your computer. Windows 7/8 should install these automatically.
- The new 4.2 updates the bootloader, removing the USB icon that used to appear there and allowed you to enter fastboot. It's OK, you will be able to use it right from the bootloader menu, without selecting any option at all.
- Do this at your own risk! I'm not responsible if you break your tablet!
- Don't forget to make BACKUPS!
- If you are already on 4.2, then you can skip to the Recovery and Root parts of this guide



-- Installing / Updating to 4.2.1 --

There are three methods you can use to update your tablet to the latest Android stock version. All of them will require you to download the
firmware file located at Asus website. You can download them from here. Select Android as the OS, firmware and choose the right firmware for you SKU. You can find your SKU by following the instructions on the website itself. Don't forget to unpack the zip file you downloaded: there's another inside!



[BOTH BL] Method 1: Updating directly from stock ROM

Notes:
  • You must have a stock ROM installed
  • You need to put the update file on an SD card
  • You will keep all your data
  • I do not recommend this method: sometimes it ends up on a brick

If your tablet is stock, or have some custom ROM based on stock installed, you can directly update the tablet by simply inserting a SD Card with the firmware file inside. Android will prompt you with a notification asking if you want to update. Touch it and wait until the update is done



[UNLOCKED BL] Method 2: Update using fastboot

Notes:
  • You will keep all your data
  • This is the best method to update your tablet if you want to keep all your data, and the safest one
  • Ensure you have the correct drivers for the tablet installed on your computer, or you will have a "waiting for device" error


To update using fastboot, follow this steps:
  1. If you don't have fastboot yet, download it from here an unpack it somewhere on your computer
  2. Extract the Asus firmware file and put the blob file inside fastboot folder
  3. Open a command line on fastboot folder (write "cmd" on Windows search bar at the Start menu, and then
    Code:
    cd "FOLDER WHERE YOU EXTRACTED FASTBOOT"
    , or you can just use SHIFT + RIGHT CLICK on the folder and select "Open command line window here" or something like that)
  4. Reboot the tablet holding the volume down key until you see some icons. Use the volume down key to select the USB icon and then volume up to select it
  5. Connect the tablet to the computer if you didn't do so
  6. Write
    Code:
    fastboot -i 0x0B05 flash staging blob
    , hit enter and wait until it completes
  7. Hold the power button for 10 seconds to reboot the tablet
  8. You are now updated to Android 4.2


[UNLOCKED BL] Method 3: Update using TWRP recovery

Notes:
  • You must have TWRP installed
  • You need to put the update file on an SD card
  • This was the method I used since I wanted to prevent any bugs due to old data and to ensure the new partitions from 4.2 would be OK
  • You will keep your data as long as you don't wipe Data and Factory reset (including internal memory)

Follow the steps bellow if you want to update to 4.2.1 DELETING ALL YOUR DATA , STARTING FROM SCRATCH!
  1. Insert the SD card with the update file on the tablet
  2. Reboot to recovery
  3. Wipe Cache, Dalvik and System. Wipe Data if you want a fresh start on your tablet, but remember, THIS WILL WIPE ALL YOUR DATA AND INTERNAL MEMORY!!. You can also do a Factory Reset instead of data wipe if you want to remove all your android configurations/apps keeping your internal storage.
  4. Install the Asus Firmware
  5. Reboot (ignore the "no OS installed message) and let it finish
  6. You have now the latest Android 4.2.1



[UNLOCKED BL]-- Installing TWRP (Recovery) --

Since this new update brings a new bootloader, older recovery versions from 4.1 won't work at all. Don't try to flash one!
This guide will give you a recovery that works just fine on the new bootloader. And yes, it can read/write to an external SD just fine. Follow this steps to install the new recovery on your device:
  1. Connect the tablet to the computer
  2. Reboot the tablet using the proper button on the power menu, holding Volume down until you see three icons (RCK, Android and Wipe Data)
  3. Download this file and unpack it (it contains fastboot and the TWRP 2.5.0.0 which works with the new bootloader)
  4. Open a command line on the extracted folder (you can use the instructions I wrote in Method 2 if you don't know how to do this) and type
    Code:
    fastboot -i 0x0b05 flash recovery twrp.blob
  5. Wait for the script to complete. Once it is done, reboot the tablet by holding volume down and power button for 10 seconds. Don't enter recovery directly!
  6. You have now the new recovery for Android 4.2 .


[BOTH BL] -- Rooting --


Note: If you are willing to install a custom ROM like CROMI you don't need this. Custom ROMs have root by default.

Rooting the tablet once you have a recovery is pretty easy. Here's how you can do it:

- Unlocked devices
  1. Download SuperSu zip file from here (choose the flashable version) ]and place it on a SD card or inside the root of your tablet's internal memory
  2. Reboot the tablet holding vol down, and when the three icons appear, hit volume up to enter recovery
  3. When the recovery prompts you a password, hit cancel (this is a bug from the current version of TWRP, and it should be fixed soon. It is ok to ignore it!)
  4. Flash the zip you just downloaded
  5. Wipe Dalvik/Cache (just in case)
  6. Reboot
  7. You are now rooted!


- Locked devices

If you have your bootloader locked you can root Android 4.1/4.2 by using the method discovered by Morlok8k, here: http://forum.xda-developers.com/show....php?t=2228613 (note that this isn't tested yet for the latest 10.6.1.27.5 firmware!)


[UNLOCKED BL] -- Downgrading to 4.1 or other firmware --


I was going to write a downgrade method but it seems that there is a good one here: http://forum.xda-developers.com/show....php?t=2195883
Again, do it at your own risk.


[LOCKED BL] -- Recovering your tablet from scratch --


If you are on a stock locked device and somehow got a bootloop and you can't do anything with your tablet you follow this steps to completely restore your tablet. Note that all data will be lost.

Quote:
Originally Posted by Pretoriano80

========= Recover /Downgrade from Jelly Bean to ICS/Clean Factory Restore with stock recovery =========

1) Download the latest firmware from Asus website
2) Extract the .zip file somewere on your desktop (the result will be another .zip file,use it for step 3)
3) Rename the extracted archive to "EP201_768_SDUPDATE.ZIP" (without the " ") and upload it to a MicroSD card
4) Insert the MicroSD card in your tablet and use this button combination to Power ON and go to recovery --> Start the tablet by pressing Volume Down and POWER togheter for 5 seconds ,a message will inform you that you have 5 seconds to enter the recovery,press Volume UP before the 5 seconds expire.
At this point the device will go in recovery and should start updating your firmware .

Note: Keep in mind that Windows doesn't show the known file extensions so most users don't have to put the .ZIP extension in the filename.


This tutorial is made of things I gathered on the forums: I do not own anything! Hit thanks if I helped you I will keep it updated once new things come out

A special thanks to elesbb for the fastboot methods
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12th March 2013, 11:48 PM |#2  
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This is great. Just one question for clarification: Users have reported not being able to see their External microSD's in TWRP. Is this still the case, or did the patch to TWRP alleviate this issue?
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12th March 2013, 11:54 PM |#3  
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would i need to unlock the bootloader to do this?
12th March 2013, 11:57 PM |#4  
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Quote:
Originally Posted by MrCHUPON

This is great. Just one question for clarification: Users have reported not being able to see their External microSD's in TWRP. Is this still the case, or did the patch to TWRP alleviate this issue?

Here TWRP is recognizing the external SD It lists the files and I'm doing right now a backup to it . No errors whatsoever

Here is a photo of me backing up to an 4GB SD card



And the end of it

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13th March 2013, 12:05 AM |#5  
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Quote:
Originally Posted by jobankler

would i need to unlock the bootloader to do this?

Check the OP...First item. "You must be unlocked".

So yes.
13th March 2013, 02:26 AM |#6  
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Re: [Tutorial] Rooting and installing a recovery on Android 4.2.1 (10.6.1.8+)
Hoi
My device is unlocked
Must i unlocked again for 4.2.1
Thanks hope you can help my

Sent from my ASUS Transformer Pad TF300T using xda premium
13th March 2013, 02:31 AM |#7  
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Re: [Tutorial] Rooting and installing a recovery on Android 4.2.1 (10.6.1.8+)
Quote:
Originally Posted by jackie1234

Hoi
My device is unlocked
Must i unlocked again for 4.2.1
Thanks hope you can help my

Sent from my ASUS Transformer Pad TF300T using xda premium

So I've read, upgrading does not relock you, so you shouldn't need to. For those that are locked and upgrade to 4.2.1 there is a new unlock tool to do it.

Sent from my ASUS Transformer Pad TF300T using Tapatalk 2
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13th March 2013, 02:32 AM |#8  
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Verified that this works for me. If you read ahead and placed the SuperSu zip on your SD card BEFOREhand, you can even skip one of the reboots.
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13th March 2013, 02:42 AM |#9  
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WARNING
Your instructions are wrong... You cannot flash the update using custom recovery, it will result in a brick..

Already happened with me!!! I've followed your tutorial blindly and had to sweat a bit to recover my tablet.

Change it ASAP.

Best solution to unbrick/flash is to go into fastboot and use

fastboot -i 0x0B05 flash system blob
fastboot -i 0x0B05 flash system "name of the update"
13th March 2013, 02:45 AM |#10  
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Quote:
Originally Posted by joelalmeidaptg

Hey guys! Asus released the new Android 4.2 to our beloved devices and now we are able to root it using a few steps.

Notes:
- You must be unlocked
- If you don't have 4.2.1 on your tablet yet, download it via the Asus website, unpack it, and place the file on your SD car and flash it using a custom recovery or the update notification on a stock ROM
- If you have 4.2 and want to unlock it, remember to check Asus website to download the new unlock tool available for 4.2 devices
- Please verify if you have the correct drivers for the tablet installed on your computer

Lets get started!

  1. Connect the tablet to the computer
  2. Reboot the tablet using the proper button on the power menu, holding Volume down until you see three icons (RCK, Android and Wipe Data)
  3. Download this file and unpack it (it contains fastboot and a patched version of TWRP 2.4.4.0)
  4. Open a command line on the extracted folder and type fastboot -i 0x0b05 flash recovery twrp.blob
  5. Wait for the script to complete. Once it is done, reboot the tablet by holding volume down and power button for 10 seconds. Don't enter recovery directly!
  6. Once the tablet boots up, download SuperSu zip file from here and place it on the root of your tablet's internal memory
  7. Reboot the tablet again holding vol down, and when the three icons appear, hit volume up to enter recovery
  8. When the recovery prompts you a password, hit cancel
  9. Flash the zip you just downloaded
  10. Wipe Dalvik/Cache (just in case)
  11. Reboot


Aaaaand... Congratulations, you have now a rooted stock Android 4.2.1 !!

This tutorial is made of things I gathered on the forums: I do not own anything! Hit thanks if I helped you

I have no words to thank you friend, excellent contribution.
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13th March 2013, 03:10 AM |#11  
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Re: [Tutorial] Rooting and installing a recovery on Android 4.2.1 (10.6.1.8+)
Quote:
Originally Posted by avatar_pt

Your instructions are wrong... You cannot flash the update using custom recovery, it will result in a brick..

Already happened with me!!! I've followed your tutorial blindly and had to sweat a bit to recover my tablet.

Change it ASAP.

Best solution to unbrick/flash is to go into fastboot and use

fastboot -i 0x0B05 flash system blob
fastboot -i 0x0B05 flash system "name of the update"

Did you unpack the zip downloaded from Asus?

Sent from my ST25a using xda app-developers app
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