Unable to mount /system as read-write

Question

I want to modify a file under /system. The problem is that is read-only, and even with root I cannot set it as read-write.

I've tried the following:

Root Explorer (the automatic button)
A one click app (https://play.google.com/store/apps/details?id=com.blogspot.superthomaslab.mountsystemrorw)
The following commands, on Terminal Emulator: su and after that mount -o rw,remount /system. Along with that some variants (specifiying -t, using -rw, mount -o rw,remount /system /system)

Some useful informations:

The device is a Redmi 3
Using android 5.1.1, on MIUI 6.4.7 (china developer version)
I have root access, and enabled it for the apps mentioned above
Bootloader is unlocked
No SD card
Output of mount | grep system: /dev/block/dm-0 /system ext4 ro,seclabel,relatime,discard,data=ordered 0 0

I would like to manage the /system folder directly from the phone. I'm pretty hopeless, I've tried googling 2 hours for a working solution. Thanks in advance.

Most likely a security thing with the device (mount namespace separation?). Also see: Can't mount /system as read/write, even though I'm rooted / /system cannot be remounted as RW, even when rooted (Sony Xperia E3) — Izzy, Apr 14 '16 at 11:56
The first one is for Android 4, I would like to have a confirmation before executing those commands. I've already tried the other solution. — asdm_ita, Apr 14 '16 at 14:38
Understood. As I've never been in that situation, I must pass on that part to someone else (and cannot help further). Good luck! — Izzy, Apr 14 '16 at 15:36

asdm_ita · Accepted Answer · 2016-04-16T10:10:40.170

4

I've found the source of the problem asking in the MIUI forums, the boot image will not accept a modified /system.

You have to use the adb interface: adb devices then adb disable-verity.

Disclaimer: I'm not responsible for any damage caused by these operations.

edited Apr 16 '16 at 10:10

answered Apr 15 '16 at 11:33

asdm_ita

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Unfortunately this only works on USERDEBUG builds. Still looking for what works for stock builds. – SAGExSDX Dec 23 '16 at 02:39

score 0 · Answer 2 · edited Sep 30 '19 at 20:02

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As suggested by user aalaap here, disabling Mount Namespace Separation setting in SuperSU solved this issue for me on ZP999 and SuperSU 2.82 SR5.

edited Sep 30 '19 at 20:02

Firelord

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answered Sep 30 '19 at 18:14

user307125

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Unable to mount /system as read-write

2 Answers2