Oops.

I guess.your -x left your rootfs in an unvisible state. Even for exporting.
I do hpe you will be able to mount your N9 rootfs manually from PC.
Something like mount /dev/sdb1 /mnt possibly needing some flags. And you need to find correct naming for exported partition. Have a look how (under which name) home and MyDocs are exported. And /mnt is any directory where content of your N9 rootfs will be shown.
But there will be nothing because you prohibited (with chmod -x) to display any content of that directory.
And I do not know how you may achieve to set some rights to something you are not allowed to see (even as root).

You will need Google to help you out to get the right file system rights back.
Have a look here e.g.
https://unix.stackexchange.com/quest...-777-in-ubuntu
as you have another N9 with intact file system. But do not execute that command as it will try to change every file rights recursively and you only need it for the first level items.

Sorry, this is kind of vague. But I was never in such circumstance.