Hello, i recently got a Galaxy 2 I9100 with Android Jellybean. I'd like to get Youtube on it, is there any way to do this? I have tried, but havent found anything helpful. Thanks in advance!
You'll have to use a modified version to work on older devices, one that is also built to work on your specific CPU architecture. You'll may also need to disable auto updates in Playstore so that it doesn't auto update and potentially cause issues.
You can also try flashing a Gapps.zip via your stock recovery, if I remember correctly, a gapps.zip can be flashed via stock recovery.
Try doing a Google search for:
Go to the Opengapps page, in the options on the page, select 4.4 or older, then select your CPU architecture, then select a Gapps package that has Youtube in it(micro, pico, etc .) You should be able to find information on the Gapps somewhere that shows which Google apps are in which Gapps zip files.
Download the Gapps file and store it in your internal or external storage then boot into recovery and select the "apply update via SD card" then find the Gapps file and flash it. After you flash it, make sure to wipe the cache partition but do not factory reset. Then reboot and see if it worked.
Even with all that, I think what I said at the top about using a modified version is the way you're going to have to go.
The I9100 is also very easily rooted and there are probably still some custom ROMs available for it here at XDA.