On my rooted device running Android 4.2.2, I have following tools installed:
- Terminal Emulator
- BusyBox Free
On Terminal Emulator,
su command successfully changes user to a real root:
root@hwH30-U10:/ # id -u uid=0(root) gid=0(root)
root@hwH30-U10:/ # mount | grep system /emmc@android /system ext4 rw,realtime,noauto_da_alloc,commit=1,data=ordered 0 0
Then I even:
root@hwH30-U10:/ # chmod 777 /system
But I can not change any thing e.g. permissions or contents of
/system original files like
I am sure that permissions and mounts are OK because I can create a new file,
/system/tmp.prop, change it's contents and permissions by Terminal Emulator.
I really have no idea why these operations are not permitted while in Linux point of view, all things are OK for root to do these changes!
Is there any hard-coded further protection inside Android e.g. in kernel?
How to figure out this, please?