Update Samsung Galaxy S3 I9300 to Official CM 10.1 Nightly Build (Android 4.2.1-based ROM)

Install Official CM10.1 Nightlies Build ROM on Samsung Galaxy S3

Samsung Galaxy S3 has received its own official CyanogenMod 10.1 Nightly Build and now you can easily learn how to install it by using the instructions in this post. This is an official CM 10.1 nightly build and it would be better if you would install it on a stock Android 4.1.x or even 4.2 Jelly Bean device. Read the entire post and make sure that you don’t skip any steps that I have listed.

The CyanogenMod 10.1 is based on the latest Google OS, Android 4.2.1 Jelly Bean and it packs all of its stock features. All bloatware has been removed and there is simply a vanilla / AOSP Android OS with a couple of other CM-based functions. Despite the fact that it is almost 100& functional, there are some components that aren’t working such as the Camera Recording effects, Touch-to-focus in Camera with the enabled Flashlight, Bluetooth audio streaming is lagging and the FM Radio works only with an app from the Google Play Store. TV Out is also not supported and it will never work with CM builds. Also, exFAT ext SD cards will not work with CyanogenMod 10.1 builds and you will have to format the external SD cards to FAT32.  There aren’t any other major bugs.

If you want to successfully flash the official CM10.1 Nightly build on your Samsung Galaxy S3 phone, then you should read the preparation guide below first:

  • Install the CM10.1 ROM zip you find in this post only for the Samsung Galaxy S3 model number I9300. It doesn’t work with any other Galaxy S3 device model.
  • This is a guide that will work with rooted I9300 devices. Also, you will need for it to have the CWM Recovery install on it or any other custom recovery image. Rooting guide for this device can be found HERE. To install CWM Recovery use this guide HERE. Without these you cannot flash the new custom Android 4.2.1 firmware.
  • Use the custom Recovery mode to create a full NANDROID backup of your currently installed ROM. This will act as cover for your phone in case something goes wrong and you brick the device or you cannot boot with CM 10.1 ROM.
  • Enable the USB debugging option from your device’s Developer Options.
  • The tutorial will ask you to wipe data and factory reset the device and, this means that you can choose to backup your SMS, Call Log and the APN Internet Settings or even save a list of installed applications. Use the following Android tools: SMS backup & restore | Call Logs backup & restore | APN Settings Backup & Restore | AppBack for Android application. Some of these tools will ask for root access.
  • Sync your Gmail Account with your Contacts application so that you will be able to restore all your saved numbers and contact details on your device after installing CM 10.1 Nightlies ROM.
  • Charge your phone’s battery so that it won’t power off in the middle of the updating process.
  • Read the entire tutorial and make sure that you know what you’re doing before starting to apply the actions listed below.
  • We cannot be held responsible in case you lose any data files nor for any bricked devices.

These were all the guidelines that you had to read before getting to the most interesting part of this post. Make sure that you don’t skip any steps listed below and that you will use the comments section in case you’re hitting any brick walls while trying to flash one of the best Android 4.2.1-based operating systems.

How to install Official CM 10.1 Nightly ROM on Samsung Galaxy S3:

  1. Download the CM10.1 ROM zip from HERE. Save the file on your PC desktop screen and don’t unzip it.
  2. Next, download the Gapps for CM10.1 and Android 4.2.1 from HERE. This zip contains all the Google applications that you need in order to get the best Jelly Bean experience. Make sure to download the Gapps for CM10.1 and Android 4.2.1 file and not some other version.
  3. Connect your smartphone to your computer. Move both files, the CM 10.1 and Gapps zips, on your smartphone’s internal SD card and when the transfer is done, disconnect the SGS3 from your PC.
  4. Power off the phone and then boot it into Recovery mode. Press the Volume Up, Home and Power to boot into ClockworkMod Recovery, which is also when you can release those buttons. Get to the next step.
  5. If you don’t have a backup then you will be forced to use the ‘backup and restore’ option and make one. Make sure that you save the backup on the phone’s internal SD card. If you already have one then you should skip this step.
  6. Select ‘wipe data/ factory reset’ option and confirm this step. This will delete the contents of the /system partition.
  7. Select ‘install zip from sdcard’ and then ‘choose zip from sdcard’. Find the CM10.1 ROM zip and confirm that you want to install it. When the ROM is installed you should get to the next step.
  8. Select ‘choose zip from sdcard’ again and then find the Gapps zip. Confirm the installation.
  9. When the Gapps is installed you can return to the main CWM Recovery menu.
  10. Select ‘reboot system now’ and then wait for the first boot process of CyanogenMod 10.1 Nightly ROM loads all the required files.
  11. Enter your Google Account credentials when the welcoming screen appears.
  12. Test the new ROM and tell us in comments if you find any major bugs.

These were all the steps that you had to take and now you should begin to test all the CM 10.1 Android 4.2.1 functions and features.

If the custom ROM doesn’t install at your first attempt, then you will have to repeat the entire tutorial once again and try to flash the files until the ROM installs.

If you want to continue updating your device with a new CM10.1 nightly build then you can find the CyanogenMod Updates option in Settings> About phone menu. If you want any extra information, then you should ask for more help in our comments field.

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