Installing both won't help since grub-efi can't chain load bios booting Windows. There's really nothing we can do to work around this insanity. You just need to decide if you are going to use uefi or not, and stick with that decision.
** Changed in: ubiquity (Ubuntu) Status: Confirmed => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1050940 Title: Ubiquity fails creating a correct Windows dualboot on EFI computers (grub-pc <-> grub-efi) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1050940/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs