remount /mnt as read-write I am getting error "Read-only filesystem" when trying to add a new directory in /mnt via Terminal Emulator. So, I tried :

su
busybox mount -o remount,rw /mnt


in order to remount filesystem for /mnt as read-write; but I am getting error "can't find /mnt in /proc/mounts".

What is this error for !?

PS. My ultimate aim is to then mount an external storage on that new directory; say /mnt/myextdrive
Use these commands

su -c 'busybox mount -o remount,rw /'    # this will remount rootfs at / in rw mode
su -c 'mkdir /mnt/"NEW_DIR"'             # replace NEW_DIR with the name of the directory you aim to create under /mnt


Note that in Android /mnt is not a mount point for any real or pseudo-filesystem but its sub-directories are (actually, /mnt is a sub-directory of the / (rootFS), which is why you'd have to remount that to apply changes here). Also note that mnt directory in Android is created by kernel at every boot1  so any modification would be lost after shutdown.



1: mnt doesn't exist in a persistent filesystem but in a specific ramfs named rootfs - a filesystem which exists in RAM only.