Using kubuntu liveCD in persistent mode, I'd like to allow user to write on boot usb key (to put data out of "casper" file).

  • USB (root) is auto mounted in /cdrom
  • kubuntu is "main" user (uid 999)

Up to now:

kubuntu@kubuntu>touch /cdrom test
touch: cannot touch '/cdrom/test': Permission denied
kubuntu@kubuntu>sudo touch /cdrom test   ==> IT WORKS

So I'd like to set "ownership" to kubuntu user, OR set permission to 777 (as "last chance")

kubuntu@kubuntu:/cdrom$ cat /etc/mtab | grep sdb1
/dev/sdb1 /cdrom vfat rw,noatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro 0 0

I've tried:

kubuntu@kubuntu:/cdrom$ sudo mount -o remount,rw /cdrom
kubuntu@kubuntu:/cdrom$ sudo mount -o remount,rw,uid=999,gid=999 /cdrom 
kubuntu@kubuntu:/cdrom$ sudo mount -o remount,rw,uid=999,gid=999,umask=0000 /cdrom

No change...

even tried to modify fstab and add this:

/dev/sdb1 /cdrom vfat rw,noatime,fmask=0000,dmask=0000,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro,uid=999,gid=999 0 0

without luck.

How to allow kubuntu user to write on this key ?

  • Why do you want to write in /cdrom ? This is the place where the Live CD is mounted. Obviously, it is read-only. If you use persistence, the rest of the root fs should be writeable. – solsTiCe Jul 12 '15 at 13:51

Just install the Live CD on a USB stick, as you would do on a normal hard drive.

This worked for me a few years ago. I booted my Live ISO in a VirtualBox, mounted the USB and installed it like any Ubuntu (Debian) derived distro.

I hope my answer is not to short :)


A live cd rom is not writable when running a operating system from it. I really don't think you could implement any sort of persistence to it. A USB drive however can be used to install a operating system on, that would then allow you to obtain the persistence you require

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