The Galaxy S3 i9300 is one of the lucky few handsets to receive both custom ROM and Samsung's official stock ROM updates porting Jelly Bean software in recent times. Thanks to XDA senior member jimbo77, the i9300 gets yet another custom ROM Android 4.1 (Jelly Bean) update with MIUI ROM.
The new MIUI ROM offers all the features of the stock Jelly Bean update, besides adding MIUI's unique interface and exquisite features such as inbuilt theme engine with a variety of custom themes available, enhanced and highly-customised notifications menu, privacy protection and more that deliver the ultimate Android experience.
This is not an official Samsung release and hence may harbour a few untested bugs or broken features, while some native apps in stock Samsung ROM may be unavailable or partly functional.
- The ROM and the instructions provided in this guide are applicable only for the Galaxy S3 i9300 and will not work with the US variants or any other device. Verify your device's model number through Settings > About phone.
- IBTimes UK advises users to backup apps, important data and settings (bookmarks, contacts, SMS, APNs and other internet settings) to avoid data loss while installing the Jelly Bean update.
- Ensure that you have ClockworkMod recovery installed on your phone before you attempt installing the firmware update.
- The instructions provided in this guide are meant for reference purpose only and do not cover any warranty claims involving device damage or issues arising out of using this Jelly Bean update. Users are advised to proceed at their own risk.
How to Install MIUI ROM Based Jelly Bean Update on Galaxy S3 i9300
Step 1: Download the latest version of MIUI ROM from XDA Developers official thread posted here.
Step 2: Without extracting, copy the downloaded zip file in step 1 to the internal SD card.
Step 3: Now, power off the device and boot into ClockworkMod recovery. To do this, press and hold down Volume Up, Home and Power buttons together until the screen powers on, then release them. The phone should instantly boot into ClockworkMod recovery. Within recovery, use the volume buttons to navigate through menu options and the home button to select an option.
Step 4: Do a Nandroid Backup of your current ROM, which helps restore your original ROM from recovery if something goes wrong with the new ROM. To do a backup, choose Backup and Restore and on the next screen, hit Backup again. The backup is time consuming and may take up to 10 minutes. Return to main recovery menu once backup is done.
Step 5: Tap wipe data/factory reset and then click Yes on next screen to confirm. Wait until the wipe is complete.
Step 6: Choose install zip from sdcard and then tap choose zip from sdcard. Locate to the ROM file and select it. Confirm installation by clicking Yes on the next screen. The ROM should begin installing.
Step 7: After the ROM is installed, choose go back then tap reboot system now to reboot the phone into MIUI ROM. First boot may take about 5 to 7 minutes.
NOTE: If you want to return to your previous ROM for some reason, boot into recovery (using the procedure explained in step 3), choose backup and restore, then restore your previous ROM by selecting it from the list.
[Source: The Android Soul]