Samsung Galaxy S3 has a 4.8″ 720p display. It also was the first device to have a quad-core Exynos 4412 processor, with each core clocked at a maximum 1.4 GHz. It packs NFC, wireless charging capability, and the latest wireless radios. It ships with Samsung’s Nature UX interface. At the time of its launch, it ran on Android 4.0.4 ICS.
The Galaxy S3 is almost 3 years old now so Samsung has stopped the official support for this device. However the guys of the CyanogenMod team have continued their work for this device and have come with CM 12.1 ROM for this device. It will update the S3 to Android 5.1 and bring along the CyanogenMod goodies. Follow the guide below to install it on the S3.
Disclaimer: Follow the instructions at your own risk. If the device gets damaged, the writer or the owner of the site must not be held responsible.
Pre-requisites and Backing up your Galaxy S3:
- Create a Nandroid Backup
- Backup and Restore your Android smartphone via Desktop PC
- Backup/Sync and Restore contacts on Android smartphone
- Backup WhatsApp messages on Android Smartphone and Email
Steps to install CM 12.1 ROM Galaxy S3:
- Create a Nandroid backup from recovery, in case anything goes wrong.
- Download the CM 12.1 ROM zip file and Gapps zip file and transfer it to the phone.
- Switch off the phone and boot the phone into Recovery mode.
- Next, wipe the cache and the dalvik cache.
- Now go to “Install zip” and then “Select zip”. Choose the CM 12.1 ROM zip file.
- Now again clear cache and dalvik cache.
- Go to ”Install zip”, then “Select zip”. Choose the Gapps zip file.
- Then perform full data wipe task. To do so, click “Wipe Data/Factory Reset”, then choose “Yes” on next screen to confirm.
- After the process is complete, reboot the phone.