Install 3rd party apps as system apps

Here is the very useful command to install a common app as system app. It's not necessary to say that's mandatory that the device needs to be rooted!

#remount system partition with read and write capabilities
#move the app from the sdcard to the /system/app directory
#remount again as read only
#reboot the device

List of commands:

adb shell
mount -o remount,rw -t yaffs2 /dev/block/mtdblock3 /system
cat /sdcard/myApp.apk > /system/app/myApp.apk
mount -o remount,ro -t yaffs2 /dev/block/mtdblock3 /system