Comment # 47 on bug 1055641 from Franck Bui

(In reply to Olli Tuominen from comment #45)
> Created attachment 740651 [details]
> screenshot of cat /proc/mounts

Thanks Olli but you ran the command when you break at the "pre-shutdown" phase,
see the shell prompt which is "pre-shutdown:/#" 

I was interested to run the commands at the "shutdown" phase/step. You normally
should break there once you exited from the "pre-shutdown" debug shell since
you normmally did:

 # echo "rd.debug rd.break=pre-shutdown rd.break=shutdown" >
/run/initramfs/etc/cmdline.d/debug.conf

as indicated in comment #14.