Because official servers for these older projects may be offline, the primary hubs to find mirror links and active developer threads are the XDA Forums Galaxy S2 Hub or community-maintained mirrors on AndroidFileHost Samsung Galaxy S2 Files . 1. CyanogenMod 12.1 (Unofficial)
Follow these sequential steps precisely after downloading the file and the corresponding Lollipop GApps .zip (Google Apps) file. gti9100 firmware 511 download upd
Navigate using the volume keys and select the Power button to execute a Wipe Data / Factory Reset . Because official servers for these older projects may
Select Wipe Cache Partition and go to advanced settings to trigger a Wipe Dalvik Cache . Navigate using the volume keys and select the
The most popular base for Android 5.1.1 builds on this legacy hardware.
Select Reboot System Now . Note that the initial boot cycle after upgrading Android versions can take up to 10 minutes to load completely.