Comment 4 for bug 447890

I'd like to dispute this bug, since the link to the documentation does not actually say that the preseed/run command should be run at the same time as late_command (anymore? this is an old bug)

At the present writing time, the documentation goes on about how the preseed/run command can be used to run a script to modify preseed parameters and to redo the network configuration.

This makes sense to do as early in the installer as possible, for example to redo network configuration, perform strange and unusual partitioning and other useful and less useful things to have maximum freedom when installing ubuntu.

I recommend using the preseed/late_command instead, for example like this:

d-i preseed/late_command string chroot /target sh -c "/usr/bin/wget -O /tmp/late_script http://preseedserver/late_script && /bin/sh -x /tmp/late_script"