Hi my question is how to upgrade to jelly bean? I have a Samsung Galaxy 2. I am use to Jelly bean that what my tablet is,so I am 1st time user of this phone I purchased. I was trying in google store to get my game on my phone and it said it was not compatible.So went in setting saw software update but when I tried to it said no firm ware. It is a second hand phone so I don't know what to do. I thought maybe if I could upgrade to jelly bean it all problems. Idk if I could find a site that has a free upgrade download. If you know a site I can do this please let me know. I don't have a USB cable just a home charger, do I need one? Ty in advance, Wendy
What you need to do is root your phone and flash a custom ROM. I'll try to give you a pretty detailed answer to your question. The S2 is pretty old so I'm sure you're not concerned about voiding any warranties, correct? If it is under some carrier (Sprint, ATT, etc.) waranty, then you're pretty much out of luck unless you don't care about voiding it. There are ways to un-flash smartphones, but I would't recommend it. Anyway, onto flashing....
Rooting and flashing a new rom is a technical task so if you're not up to it you could probably find a friend (or someone on Craigslist, etc.) to root it and flash a custom rom for you. It will definitely take a few hours since it's your first time doing it, and it can be a real pain if you run into a problem. I rarely have, but you never know. You can always come back to the forum and post the problem or ask on the YouTube channels recommended below.
If you decide to procede, I take no responsibility if you break your phone. First do a YouTube (or Google) search for "Flash CyanogenMod 11 4.4.4 (Insert Carrier Name Here) Galaxy S2". You should be able to look through a few pages and find a (well written) tutorial that will guide you through rooting your S2 and flashing a custom rom.
Tip: Verify that you're able to download all of the necessary files before you even plug your S2 into your PC and start to root it (and yes, you will need a USB cable). Most of the headaches I've encountered had to do with getting half way through the install process only to come across a dead download link, and then not being able to easily find the exact same file I needed somewhere else. Also, some of the roms have some bugs. Most of them don't but it is something to be aware of if something like your GPS doesn't work. Once your phone's rooted you'll be able to just reboot it, boot into recovery mode, and flash another rom (without having to completely re-root your phone). You may have to do another search for how to re-boot into recovery mode for your specific cell phone carrier. You should be able to simply turn off the phone and then when you turn it back on, keep holding the power button down instead of letting it go in addition to the volume down button. Then just repeat the steps from the tutorial page (definitely bookmark the tutorial, in case you ever need to refer back to it) to flash a different rom.
I really hope this post helps you understand the tech lingo a little bit better and that you're able to get your S2 rooted easily. I didn't know anything about rooting a few years before I rooted my first phone, and I learned nearly everything needed within the first day! If you set aside a day or two to root your phone, flash a custom rom, and explore all of the settings of the new rom you'll be glad you did. It sucks if you're out and about and need to change a setting but have no idea where it is because all of your settings menus changed.
If you have any issues or questions, please post back here and I'll help as much as possible. I've rooted many phones and flashed a couple dozen roms so I do have a bit of experience with the process. I was actually going to do a short tutorial myself but StackExchange shut me down and said I could only use two links in my post because I didn't have enough reputation points :(.
Good luck and I hope everything goes smoothly for you!