Samsung Galaxy S III android(5.1.1) CM12
HowTo Flash Samsung S3 I9300 to adroid lolipop 5.1.1
1. Download the appropriate ROM using links provide in the post.
2. Download the appropriate GApps following the links in the post.
2. Download the appropriate GApps following the links in the post.
3. Back up any and all important data.
5. WIPE DALVIK/CACHE/DATA/FACTORY RESET.
6. WIPE SYSTEM.
7. Flash the ROM in recovery.how to get in recovery mode.
7.1. DO NOT FIX PERMISSIONS AFTER FLASHING, doing so will cause a bootloop.
8. Flash the GApps.
9. WIPE DALVIK/CACHE (for good measure).
10. Reboot Device.
5. WIPE DALVIK/CACHE/DATA/FACTORY RESET.
6. WIPE SYSTEM.
7. Flash the ROM in recovery.how to get in recovery mode.
7.1. DO NOT FIX PERMISSIONS AFTER FLASHING, doing so will cause a bootloop.
8. Flash the GApps.
9. WIPE DALVIK/CACHE (for good measure).
10. Reboot Device.
11.That all thank you

credit: Xda developer