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/system won't stay mounted as rw

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chris.davis925
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Default /system won't stay mounted as rw

Hello all,

I have been trying to gain root on a Android 4.0.4 device and was able to, but I can't seem to keep system rw long term.

I run the following command

mount -o remount,rw /system
or
adb remount (from a PC)

the mount command will then show that system is in rw mode. However, if I attempt to copy any data into /system, the first file copy fails and the system then reports read only. To make things even more odd, commands like chmod on a file in /system work just fine.

It seems to me that there is something that detects something writing to /system, and then forces the mount back to ro.

Does anyone have any ideas about this? Is this a common technique manufactures use?
The closest thing I could find on XDA is a reference to Sony Xperia devices having a watchdog service that doesn't something like this, but this device is a Kenwood Head unit and not a Sony device.

Thanks!
 
es0tericcha0s
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Quote:
Originally Posted by chris.davis925 View Post
Hello all,

I have been trying to gain root on a Android 4.0.4 device and was able to, but I can't seem to keep system rw long term.

I run the following command

mount -o remount,rw /system
or
adb remount (from a PC)

the mount command will then show that system is in rw mode. However, if I attempt to copy any data into /system, the first file copy fails and the system then reports read only. To make things even more odd, commands like chmod on a file in /system work just fine.

It seems to me that there is something that detects something writing to /system, and then forces the mount back to ro.

Does anyone have any ideas about this? Is this a common technique manufactures use?
The closest thing I could find on XDA is a reference to Sony Xperia devices having a watchdog service that doesn't something like this, but this device is a Kenwood Head unit and not a Sony device.

Thanks!
I would think that you might need to run a script to remount on boot perhaps, such as one along this idea http://www.3c71.com/android/?q=node/466. Like via init.d or if that isn't possible on this then maybe something like this could do it http://forum.xda-developers.com/show....php?t=2378274 ?


Just spit balling ideas.
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chris.davis925
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Correct me if I am wrong, but it seems to me that I wouldn't be able to do those options since system doesn't actually stay rw?
 
es0tericcha0s
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Really depends on the phone. Sometimes you can slip a script in during boot that will keep the system open. Sometimes you need to have a special module too such as this: http://forum.xda-developers.com/show....php?t=2230341 Sometimes the kernel doesn't allow it. I would think on 4.0.4 it shouldn't be near as hard as some of the newer JB and KK things. What do you have?
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chris.davis925
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It is the Kenwood DNN990HD running Android 4.0.4.

I will try and run the binary tool you linked.
Thanks!
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