XDA University: Crafting Recovery-Flashable Packages
Those of us who use Linux on a day to day basis don’t think twice about sinking our fingers into the system files that govern how our devices perform. For instance, I use an LG L9 and was quite comfortable playing around with the way my SD card was being mounted in order to improve performance. For those who aren’t at home with the way the OS works, adding a startup script with a few lines of code might as well be witchcraft. That’s why flashable zip files are so handy for simple tasks and indispensable for complex projects. If you do it right, all the end-user needs do is copy a file to his SD card and reboot into recovery to flash the package.
There are some automatic tools out there that can help create these files. In fact, we’ve already covered at least one of them. But there’s really no substitute for knowing exactly what goes into one. XDA Senior Member Denkantor can explain it all, and decided to make an XDA University guide on package for flashing from recovery. Head on over to his original thread to see what he’s up to.
It doesn’t take much to make an update.zip file. Denkantor likes to use 7zip. And if you’re on Windows, he recommends Notepad++. You’ll also need the file(s) you want to flash. The Edify scripting language is what a custom recovery is looking for. You’ll be guided through the basics, but learning more is easy since you can look at any flashable file as an example.