I just [successfully] upgraded my Android phone  from Jelly Bean (4.1.2) to KitKat (4.4.2). Here are some notes about my upgrade process.
- Backup your data before trying anything! In particular, make sure it is available elsewhere: either in the cloud or in a computer.
- Make screenshots of the apps you have installed: use your launcher plus <VolumeDown> + <Power> buttons pressed together for a while. And…save these screenshots somewhere!
- Did you backup your data??????
- Is your bootloader unlocked? If not, then you should probably unlock it first. A good reference for this is .
- Is your device rooted? Maybe you should do that first. See .
- What do you want do to? Upgrade your android (version)? Then search for “OTA upgrade”. Customize it? Then search for “custom ROM”.
- Make sure to get a decent recovery. TWRP (TeamWin) looks like one of the best today. Another option is CWM. A recovery is something that will be useful if you want to flash ZIPs, wipe your cache, install custom ROMs…in other words, for maintenance and customization tasks (anything, for that matter).
- To reboot your phone with adb directly into the bootloader: `adb reboot-bootloader`
- Or maybe into the recovery: `adb reboot recovery`
- While you are in fastboot, you cannot use adb.
- Here is a good source to get an updated adb: ftp://ftp.mozilla.org/pub/labs/android-tools/
- Usually you can upgrade your phone either from Windows or Linux. I usually use Windows for this task, since it looks like what most power android developers and users use. Is this true? I don’t know. But the method should be reliable: use what is available and recommended by the tutorial you’re reading.
- Don’t simply install blindly: read, read and read before anything else! In particular, see opinions of other users.
- If you need support, use IRC (on Freenode: see the #android-root channel), Facebook Groups or Google+ groups. Reddit is another good place. What is the best one? That depends on the size and the activity of each community. Try to search for a group about your phone model or family first. XDA forums is usually a technical/advanced place: don’t ask newbie questions in there, unless there is specifically a section for them — or, unless if you have a specific question about a specific thread –> in this case, ask for support in the thread.
- Debloating is a good term to search for after you finish installing/upgrading your device.
- Google Play is not the only thing out there; see also F-Droid (it contains FOSS software).
- Only upgrade your phone with a charger connected.
- Don’t install untested or poorly tested ROMs. It is better not to install anything instead of installing something that doesn’t work very well –> this won’t be always true, use your head and inspect the context carefully.
I guess those items sums up some key points. If you want to complement this post, feel free to leave a comment. Happy hacking!
: a Motorola Razr I XT890, with an Intel Atom (x86) CPU and 1GB of RAM
: XDA Developer Forums: http://forum.xda-developers.com/