Connect the Galaxy S2 to a PC via USB and move both downloaded .zip files directly to the root directory of the phone’s internal storage or external SD card.
was never officially released by Samsung for the classic Galaxy S2 (GT-I9100) . The manufacturer stopped official firmware support at Android 4.1.2 Jelly Bean. Enthusiasts must rely on Custom ROMs to run Android 5.1.1 on this specific hardware. gti9100 firmware 511 download upd
Select Wipe Cache Partition and go to advanced settings to trigger a Wipe Dalvik Cache . Connect the Galaxy S2 to a PC via
Once the ROM is complete, repeat the installation process for the GApps .zip file without rebooting first. Enthusiasts must rely on Custom ROMs to run Android 5
Return to the main recovery menu, click Install Zip , find your downloaded ROM .zip file, and confirm the installation.
Power off the device entirely. Hold down the Volume Up + Home + Power buttons simultaneously until the recovery menu screen displays.