Update AT&T Samsung Galaxy S3 I9300 to Asylum CM10 Jelly Bean Custom ROM

AT&T Galaxy S3 updated with Asylum CM10 Jelly Bean Custom ROM

The AT&T variant of Galaxy S3 has received a brand new custom ROM called Asylum and it is based on CM10 Jelly Bean 4.1. In this post you will find all the instructions required in order to correctly update your device to a custom Jelly Bean custom ROM.

Asylum CM10 has been built from CM10 code source and it comes with numerous optimized features, functions and services. It doesn’t pack any bloatware, Apex Launcher is the default home launcher. Currently, the ROM is in development state and it might still pack some errors and bugs. If you want to correctly install this ROM, you will first need to read the preparation guide and learn what steps are needed so that you will manage to flash all files at your first attempt.

Asylum custom ROM is based on the CM10 by CyanogenMod team and it packs all the CM basic features. Make sure that you post in our comments any problems you might find in this ROM so that other users will know exactly what to expect from it. Also, it is recommended for you to create a full NANDROID backup of the existing before installing Asylum. More about this can be found in the prep guide below:

  • This tutorial works exclusively with the AT&T Samsung Galaxy S3 model number I747. Do not attempt to install it on any other device as it won’t work. Check your phone’s model number and carrier by opening Settings and checking the info listed under ‘About device’.
  • The phone should be rooted and the CWM recovery image has to be installed on it. Do not continue with the tutorial in case your device isn’t rooted.
  • Create a backup of your entire ROM using CWM recovery mode or ROM manager. This backup will prove to be extremely helpful in case something goes wrong during the update process.
  • Move all important files on your computer. Also, you can choose to move the files on your device’s internal sdcard, as this part of your device won’t be deleted by the installation of Asylum custom ROM.
  • Save a list of all installed applications using the AppBack for Android.
  • The SMS, Call Logs and the APN internet Settings app should be backed up using the following tools for Android:  SMS backup & restore | Call Logs backup & restore | APN Settings Backup & Restore. Note that these apps will work with rooted devices only.
  • Phone Contacts should be synced with your Gmail account.
  • Enable USB debugging mode option from the Android Development menu.
  • Remember to charge your phone’s battery so that the device won’t power off while you’re installing the new custom ROM.
  • Use this guide only if you’re an advanced Android user. Do not attempt to flash the ROM files if you’re a novice.
  • Note that we cannot be held responsible in case you damage your device in the process.
  • This custom ROM might pack some errors and bugs, as it is in development stage. Post all the errors you find in comments.

I think that these are all the guidelines you had to read prior to installing the ROM. Now you should move to the tutorial. Make sure that you don’t skip any steps as that will result in a failed attempt of updating your device.

How to update AT&T Galaxy S3 with Asylum CM10 Jelly Bean custom ROM

  1. Download the Asylum custom ROM from HERE. Save the file on your PC and don’t extract your device.
  2. Next, download the Gapps for Jelly Bean HERE. Don’t extract the zip contents.
  3. Now you need to connect your device to your computer and transfer the ROM and Google Apps zips on its internal SDcard. After the transfer is complete you should unplug the device from your PC and then power it OFF. You will have to boot into a custom recovery mode after that.
  4. To boot into CWM recovery you will need to press the ‘volume up’ + ‘home’ + ‘power’ buttons at the same time. When the display powers on you should release the buttons.
  5. You can create a full backup of your ROM by selecting ‘backup and restore’ option from CWM recovery main screen. After the backup is complete you can continue to the next step. Also, if you already made a backup then you should skip the step.
  6. Now, select ‘wipe data/ factory reset’ and then confirm this action.
  7. Select ‘install zip from sdcard’ and then ‘choose zip from sdcard’ and find the Asylum ROM zip file. Confirm the installation and when you’re done you should return to the main recovery menu.
  8. Repeat step 7 and this time you need to install the Gapps zip. After you’ve installed the ROM and the Google Apps then you should go back to the CWM recovery main screen.
  9. Select ‘reboot system now’ and wait for the first boot process of Asylum CM10 Jelly Bean to complete. When that happens you should enter your Google account credentials and take control over your phone again.
  10. That’s it, now your smartphone is sporting the Asylum CM10 custom ROM and you should begin testing its features.

Note that in case the first boot process of Asylum doesn’t complete in under 15 minutes or the phone gets into a boot loop, then you should power off the device and after that you have to repeat the entire tutorial starting with step 4. Make sure that you apply step 6 as without wiping the data from the previous ROM, your AT&T Galaxy S3 won’t be able to boot normally.

I think that these are all the steps that you had to take in order to correctly flash this custom ROM on your smartphone. If you have any other questions, then you should post them in our comments field and we will try to give you extra instructions and guidance. Remember that this ROM will work only with AT&T variant of Galaxy S3 and you shouldn’t try to flash it on any other device.

If you don’t like this new ROM, then you should restore the backup of the previous one and it would like nothing was ever changed.