I have a rooted Galaxy S5 SM-G900V, lineage_klte, ARMv7 Processor rev 1 (v71), Kernel: 3.4.113-lineageos #1 SMP, Oreo 8.1 that a friend asked me to modify.

I need to modify the platform.xml file to allow the system to write data to the external sd card. I need the ability to modify this file. The current permissions are: rw-r--r-- 1 root root, however I am unable to save any modifications.

I am unable to modify the file permissions and would like to know how to do so. Note, I am looking how to change the file permissions and not how to or what syntax to use in the xml file, or if it will allow me to have the system recognize the external sd card for saving data. I am perplexed on why I am unable to modify this file.

> adb devices  <-- verify I have the device
> adb shell    <-- enter shell
> su           <-- super user
# ls -l
drwxr-xr-x  17 root   root      4096 2019-03-20 10:26     system
# cd system
#ls -l
drwxr-xr-x 20 root root     4096 2019-03-20 10:25 etc
# cd etc
 # ls -l
 > drwxr-xr-x  2 root root     560 2013-12-31 21:23 permissions
 # cd permissions
 # ls -l
 -rw-r--r-- 1 root root  9116 2008-12-31 18:00 platform.xml
 # chmod 755 platform.xml
 >> chmod: chmod 'platform.xml' to 100755: Read-only file system

So, how do I change the file attributes for platform.xml allowing it to be modified? I thought that there was a hidden immutable attribute on the file but there is not(at least that I can determine).

Related question, is there any other website to post this question? Any help is most appreciated.

  • 1
    Try remounting /system with mount -o rw,remount /system Mar 24, 2019 at 15:12
  • I get: mount: '/dev/block/platform/msm_sdcc.1/by-name/system' not user mountable in fstab
    – Nora
    Mar 24, 2019 at 15:49
  • 1
    Try installing a file manager that can get root access (MiXplorer, Root Explorer, ES File manager, etc), then check if the file manager can access read/write /system Mar 24, 2019 at 16:02
  • @Nora you must be trying without root. mount works only with root access. And don't chmod any system files, you can brick your device. With root, you can edit files without chmoding or chowning too. Mar 24, 2019 at 21:21
  • I've tried that route before, I use Root Explorer and after being granted root access I try to change the permissions and I get a error "Changing permissions was not successful. Please note...," I definitely have root, I can verify using Root Checker Pro.
    – Nora
    Mar 24, 2019 at 21:44

2 Answers 2


I was only able to remount rw after - removing addonsu (by sideloading in TWRP "su removal" from https://download.lineageos.org/extras) - installing Magisk (easy, sideloading current release from https://github.com/topjohnwu/Magisk/releases)

I was under the impression that addonsu does not fully grants permissions -- after all I found myself heading down this road when attempting to configure Titanium Backup.

By the way, TWRP has a commandline guide at https://twrp.me/faq/openrecoveryscript.html , all the above is as easy as adb reboot recovery, then adb shell twrp sideload which makes TWRP waiting for a file, so just serve it by e.g. adb shell twrp sideload ~/Downloads/Magisk-v19.3.zip


This issue relates to the fact that /system is absolutely read-only and the mount -o,rw is no longer allowed on recent versions of Android.

To modify anything in /system you need to use Magisk ability to replace files by creating a magisk module.

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