Comment 2 for bug 605149

I have not figured out why it was hanging, but I have discovered that wrapping the call in debconf-apt-progress not only presents a proper progress bar, but also somehow avoids the hang.

So, my full late_command is:

d-i preseed/late_command string in-target sh -c "debconf-apt-progress --logstderr -- aptitude -q --without-recommends -y -o DPkg::options=--force-confnew full-upgrade"

(The options that I'm using are there because I copied them from the pkgsel code handling the pkgsel/upgrade step.)