[Michel]
I don't know where is the work on upgrade documentation but I wanted
underline this order.
At least the udev issue is known to me. It can be worked around by
touching /etc/udev/kernel-upgrade before upgrading udev, allowing the
kernel and udev to be upgraded at the same time and without reboot
between them. See<URL: http://bugs.debian.org/549522>,
<URL: http://bugs.debian.org/566000> and
<URL: http://bugs.debian.org/571255> for discussion about the udev
issue.
It has been known for a while, and no-one have been able to come up
with a udev patch to avoid it, so I guess we will have to live with
this upgrade pain for Lenny->Squeeze.
Happy hacking,