The android 4.0 system is already root, but root is not thorough.
The following provides a solution to delete and modify system apps, so you do not have to re-compile the Android system every time to kill the system's apps.
1. Enable "USB debugging" on the android host"
Open cmd or terminal, Type
ADB Devices
You can check whether the current USB debugging link is normal.
2. Type "ddms" to open the ddms auxiliary tool.
Ddms
Open File explorer and jump to system/APP to view the apps installed in the system.
You can view the permissions of all apps,
For example:
D rwx R-x r-x
The first character specifies the file type. 1. If the first character is a horizontal line, it indicates a non-directory file. If it is D, it indicates a directory.
The second part is the permission attribute of the file owner.
The third part is the permission attribute of the group to which the file belongs.
The fourth section is the permission attribute for other users.
Middle
-RW-r --
Indicates a file. The owner has read and write permissions and has no operation permissions. The group and other users have only read permissions.
3. Run the following command in cmd to re-mount the android directory. Otherwise, the permission modification fails.
ADB remount
4. Enter the following command to open all permissions for the/system/APP directory (including all files under the directory.
ADB shell chmod 777/system/APP
Then you can delete or modify the system apps.