Quick & Dirty Tips: How to remove preloaded android apps

You need to have a rooted phone. Rooting of a phone is different for every device model, so it's important to find the right tools and procedure for your particular phone. Once your phone is rooted, connect your computer to your phone via USB and enable debugging via the developer options. You can now use the following set of commands in your computer terminal.

leo-osx:src_folder leo.kwong$ adb shell

shell@d2spr:/ $ su

root@d2spr:/ # mount -o rw,remount /system

root@d2spr:/ # cd system/priv-app/                                             

root@d2spr:/system/priv-app # ls MyTestApp*

MyTestAppForBlog.apk
root@d2spr:rm MyTestAppForBlog.apk
root@d2spr:/system/priv-app # exit

shell@d2spr:/ $ exit

leo-osx:src_folder leo.kwong$ 

What we're doing here is making the system folder read and write-able. Some of the preload apps will be in the system/priv-app and some will be in system/app. Only apks in /system/priv-app can use "system"-level permissions. Prior to Kitkat, all apks on the system partition could use those permissions. Uninstalling the app is just a matter of removing the APK file.

Reference: Android-Shell-Command-Reference