Samsung Galaxy S3 mini will not get the Android 5.0 Lollipop update officially, however you can enjoy the latest Android OS on it is by installing AOSP based ROMs like CyanogenMod. Novafusion custom ROM developer has released a stable Android 5.0.2 Lollipop ROM for Galaxy S3 mini. The ROM is based on the newest CyanogenMod 12.
The unofficial CyanogenMod 12 custom ROM (Android 5.0.2 Lollipop) by Novafusion is compatible with all Galaxy S3 Mini variants such as i8190, i8190L and i8190N. The ROM is almost stable and only issue is video taken by camera is green. Interested users may read on to know how to install this ROM on Galaxy S3 mini.
For installing CyanogenMod 12 unofficial ROM your Galaxy S3 mini meets certain requirements. It must be rooted and newest version of custom recoveries like TWRP or CWM installed.
IMPORTANT: Back up everything (contacts, call logs, SMS, images, video, audio and other data) before installing the custom ROM. Also, DO NOT forget to make Nandroid back up from recovery.
Disclaimer: Please follow this guide at your own risk. Though we are putting our level best to provide this tutorial at its maximum perfection and accuracy, we can’t take responsibility for anything that goes wrong. This guide is intended for technically talented users only.
Note: Download recovery version of the ROM
2. Turn off Galaxy S3 Mini and reboot it into recovery mode. To do so, press and hold Volume Up, Home, and Power button few seconds.
Note: This guide is based on CWM recovery
3. From recovery, perform a factory reset (choose “wipe data/factory reset”) and wipe cache partition (choose “Wipe Cache Partition”)
4. Now, go back to the main recovery menu and choose “Mounts and Storage” -> Format / Data -> tap on Yes. Once done, go to “Advanced” menu then choose “Wipe dalvik cache” and tap on Yes to confirm.
5. Now, select “Install Zip from SD card” option, and then tap on “Choose ZIP from from SD card”, browse the CM12.0 ROM (you have copied earlier) and tap “Yes” to begin installation.
6. Do step 5 for installing Google Apps package.
7. Once everything are done, go back to main recovery menu and choose “Reboot system now” option. It may take around 5 minutes for the device to reboot.
1. If your Galaxy S3 mini gets into the boot loop sequence (stuck in the welcome screen), boot your phone into custom recovery, perform ‘wipe cache partition’ and from ‘Advanced’ option perform ‘wipe dalvik cache’.
2. If above procedure isn’t helped you, remove battery from your phone and then re-insert it and follow the above installation instructions again.
Enjoy Android 5.0.2 Lollipop on Galaxy S3 mini.(source)