Modify the Android system file with read-only permission

Recently, I am working on Android-ndk development. Because of the need to involve the dynamic library (SO) issue, I need to read and write mobile phone files. I found that the mobile phone file system did not allow writing and I searched for it.

Solution:

Enter $ mount on the terminal

1:

It can be found that only the read permission is available (/dev/block/mmcblk0p25/system)

Modify its permissions: $ Mount-O remount/dev/block/mmcblk0p25/System

2:

3:

Add the permission for the folder to be written: chmod 777/System

Add the permission for the device to be operated: chmod 777/dev/graphics/fb0 (this is the device file I want to use, depending on the situation)

(PS: You must use the root user in Linux to modify the permission. Otherwise, the system will prompt that you do not have the permission)