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

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://xdaforums.com/showthread.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://xdaforums.com/showthread.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.

Pretoriano80 said:

========= 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.

Click to expand...

Click to collapse

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

A special thanks to elesbb for the fastboot methods

joelalmeidaptg said:

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 :angel:

Click to expand...

Click to collapse

:good: :fingers-crossed: :victory: :laugh: I have no words to thank you friend, excellent contribution.

There is a little lack of clarity which should be in the OP.

1. If a wipe is required (other than cache/dalvik), folks should know PRECISELY when to do that wipe. If NO wipe is required. it the OP should say so. I see a few posters in the thread who indicated that they did do a wipe, others who didn't mention it. A badly timed wipe can brick a unit; an undone wipe that is required can send one into a bootloop. It's an important detail --- and, for that matter, if the install script automatically wipes, then that should be stated.

2. It seems there is a difference of opinion as to the precise sequence of which flashes first TWRP 2.4.4.0 or 4.2.1 ROM (and it also appears it may not matter which goes first; (2) I saw one poster who made a big fuss about flashing the ROM via fastboot, but "flash system" will only flash the system partition, and the ROM obviously also includes a bootloader and boot partition.

3. Nobody has stated what I expect is the obvious (and there are any number of noobs running around and bricking their TF300's because they're not reading everything in the forums), but I expect this process WIPES the data partition, and therefore, all apps need to be reinstalled. I think I've seen only one poster who confirmed that he restored his backups, but he didn't state whether that was from Asus' backup software, Titanium, or some other method. Frankly, I like Apps2zip, but that's me.

Once I have some time, I intend to complete the process and then probably rewrite the entire standard operating procedure more clearly, but that isn't happening today --- and I'm still a little concerned about some bugs reported in 4.2.1 (including one involving hdmi out, and I must have working hdmi for work), so I'm not anxious to jump in whether others have clearly had issues.

Finally, I would encourage anyone already rooted and running Titanium to create a flashable zip of Titanium (it's in the menu options) and flash that after first booting the rooted ROM and preliminarily setting it up. Then return to recovery and flash the update which will install Titanium. Load Titanium, make sure it gets root, then point it to its former directory so it can restore the prior tablet device id (which will require another reboot). That way you won't use up authorizations on those apps that require device authorizations (e.g. Google Music, limited to 10, which is an issue for us flashaholics, or Amazon Market).

Ultimately, I believe the optimal updating method should be (note, I didn't say IS, because I haven't done this yet):

1. Make sure you have working fastboot on connect to PC; make sure you've backed up all your apps and data, make sure you've got the SupersSU flashable file and Titanium flashable file on the root of your internal memory (some are having issues with recovery reading removable cards). If you don't have the drivesr loaded, this isn't the thread for you, look elsewhere ("search" is your friend on xda) for how to load drivers, etc. By the way, the standard way to check if fastboot works "fastboot devices" does NOT work on the TF300T. Try to reboot the device within fastboot and if that works, you've got fastboot working.

2. Put updated ROM (4.2.1) on root of internal memory (apparently it works better if you actually extract the zip inside the zip downloaded from Asus, but that's not entirely clear either); let the system see the update from within the ROM and flash. That will probably factory restore your system (and delete all your apps and settings). Reboot to bootloader, connect to PC. Note that the new bootloader does not have the USB sign, the bootloader "defaults" to fastboot if connected to PC (this is actually more typically behavior for bootloaders than we had previously on the unit).

3. Flash updated TWRP in fastboot. Reboot to ROM. Disconnect from PC.

4. When ROM loads, do preliminary system setup. Reboot to recovery. (Some suggest that you can just flash SuperSU and Titanium, but I prefer doing things incrementally because if they break, you can go backwards to troubleshoot).

5. In recovery, flash SuperSU; flash Titanium. Reboot to ROM.

6. When ROM loads, set up SuperSU, make sure you have root; setup Titanium, restore prior device ID, reboot ROM.

At that point you should have 4.2.1, rooted, a working recovery, and be able to restore all applications in Titanium or howsoever else you like. If you're using App2Zip, this is when you'd reboot to recovery and restore the apps via zip.

That's theory. Will see whether that works in reality. Anyone who can point out a specific mistake, let me know and I'll edit.

One other thing. If you're not unlocked, DON'T DO THIS. If you don't want root access and a custom recovery, DON'T DO THIS. If you aren't willing to TAKE YOUR TIME, read ALL the relevant threads in this and other TF300T forums (the FAQ's are a good start, and there's a good itemized list of ROMs, kernels, firmware versions, too), then please don't just willy nilly flash things on your several hundred dollar tablet and then start yet another "I bricked my tab" thread. This is not for sissies. The Transformer is a finicky tablet. XDA is a "developer's-based" forum. You're supposed to SEARCH and do your homework --- otherwise, go to Android Forums or any of the other n00bfriendly sites and whine.

If you don't understand the language (this is a very international forum), find someone who does. Make sure you KNOW what you're doing. Like I said, I've flashed dozens of ROMs, recoveries, bootloaders, radios on many devices. I don't wade into this stuff. I don't do it when I'm multitasking, sitting in a class (I'm many years out of school), sitting in a courtroom (oh, well, all right, I did do a nandroid once in in court), talking with a client, sitting on the john. Clear the desk, clear the decks, focus. Or just leave it alone.

Updated the guide with the new TWRP 2.5.0.0

Please read the following warning:

Note: this guide was updated with the new 2.5.0.0 TWRP. For this to work properly, you will need to use the last 10.6.1.15.3 version of the tablet. 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 version, you will end up with a double screen!


Remember to always make your backups. I did a fresh install when updating. I didn't tried to install any custom ROMs until now, but I'll keep you posted.

Don't forget to thank!

MrCHUPON said:

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?

Click to expand...

Click to collapse

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