i have several fc5 dom0 servers booting ubuntu-based domUs with stock fc5 domU kernel and initrd, works beautifully. however, those same exact domUs fail to boot under fc6 (kernel panic, can''t find /). it''s even the same hardware (dell 2650 server) - a given domU filesystem/kernel/initrd combo works great under fc5, but fails under fc6. any thoughts?