not a good idea, IMO. I see hdinstall as a one time installation tool. After that, just apt-get. It is closed to impossible to do this kind of 'upgrade' given what I know about linux(even window may not be able to do it). Beside, why reiventing the wheel when dpkg/apt-get is designed specifically for package upgrade ? There is still lots of gotcha there which is already considered the best in linux.