- Build environment is up and running
- Temporary change sources in /etc/apt/sources.list from lucid to oneiric.
- apt-get source apt-get source xen-hypervisor-4.1-amd64 ipxe
- install ipxe via executing dpkg-buildpackage -b -rfakeroot && dpkg -i ./../ipxe*deb
- go to xen-4.1.1 and edit debian/rules.real: change dh_python2 to simply dh_python
- edit debian/control and change XS-Python-Version: 2.7 to XS-Python-Version: 2.6
- edit debian/changelog appropriately
- dpkg-buildpackage -b -rfakeroot and you are done.