I am zero for three trying to get fc18 to dual boot. I have a number of systems with fc16 or fc17 currently dual booting, some with XP as well. In every case, doing a new install into a new boot and root space, NONE of the existing installed OS were recognized, only fc18 was left bootable. I also tried fedup using the existing boot partition from fc17 in hope that it would learn from the grub config file and keep the existing boots. Didn't happen.
Is this just no longer possible, or is there magic, or do I have to try and write my own grub2 stanzas, seeing that copying the ones from the fc17 boot cfg and adding them to grub2.cfg results in some boot failure mode? It seems that fc18 just won't coexist with other Linux versions, and the next machine I need to do has XP, fc4, fc9, and is currently on fc13.
Pointer to some useful info?