# mount
** find the mount point for /system in the list of mounts (for example if you see a line that says <code>/dev/block/mmcblk0p20 /system ext4 ro,seclabel,relatime,data=ordered 0 0</code> your mount point is <code>/dev/block/mmcblk0p20</code>
# mount -o remount,rw <mount point> /system</code> as root in adb shell # (replace <device> with your device ID)
# cp -r /data/local/tmp/distribution /system/<package>/ # (replace <package> with the ID for the package you want to test, e.g. org.mozilla.fennec)