Unable to install .apk from /system/priv-app

Question

I moved my apk file to /system/priv-app just as you adviced me in this thread. When I'm trying to install it through clicking this .apk, Android said me that "The application has not been installed". I tried to use adb install myapp.apk for this purpose but again ADB gave me an error: Failure [INSTALL_FAILED_POLICY_REJECTED_PERMISSION] and I suppose that app requires permission which can be granted only by root. So the only way I see now is to run adb shell later su next cd /system/priv-app and install [-cdDsp] [-o USER] [-g GRP] [-m MODE] [-t DIR] [SOURCE]... DEST and that's a point because I totally don't understand this legend:

    Copy files and set attributes
    -c      Just copy (default)
    -d      Create directories
    -D      Create leading target directories
    -s      Strip symbol table
    -p      Preserve date
    -o USER Set ownership
    -g GRP  Set group ownership
    -m MODE Set permissions
    -t DIR  Install to DIR`

How to set attributes to install this apk as system app?

Answer 1

I think you misunderstand the whole process. You are not supposed to use install command or the likes of it anywhere in the process I mentioned. You simply:

1. mount the system partition in rw mode
2. copy-paste the apk into the location,

3. set the appropriate permissions using busybox's chmod and chgrp or through inbuilt tools:

   adb shell su -c chmod 644 APK    # replace APK with your apk's absolute location, such as /system/priv-app/xyz.apk
   adb shell su -c chown root:root APK   # replace APK as said above
   

4. do a reboot.

Follow those instructions religiously. You can altogether avoid the commands using a file manager app such as Solid File Explorer, ES File Explorer, etc.

During the following boot the Android would detect the apk and install it automatically.

Answer 2

As suggested by @Firelord, you can eliminate the hussle of entering commands (and possibly reduce the likelihood of errors) using a file explorer such as the one mentioned already.

For instance with ES explorer, simply long press the target .apk file and choose properties then edit:

Afterwards you get proper permissions i.e -rw- r-- r-- and owner i.e root:

Disclaimer: the app used above in example is my own-made app, so you won't find it in playstore

Answer 3

You should move the APK file to /system/priv-app, then change its file mode to 0664 (-rw-r--r--) and change its owner to root:root.

chmod 0644 your.apk
chown 0.0 your.apk

Then it should be fine.