I'm having trouble launching a desktop application because it requires the user running it to be a member of a particular group. I can run a root shell, but the root shell doesn't know users or groups (usermod gives error because user 'phablet' doesn't exist)..

I can run a shell as 'phablet' user, but can't do usermod because sudo won't work (sudo: /usr/bin/sudo must be owned by uid 0 and have the setuid bit set).

Seems like a catch 22!