Nixos has a configuration option in the manual for specifying extra entries in the grub menu
boot.loader.grub. extraEntries but I can't get it to work with the examples in the manual. The idea is to let the version of grub installed by nixos have extra entries for other bootable partitions. For example, if Ubuntu (or Debian or BSD, etc) were installed and booting from /dev/sda2, one should be able to install nixos to /dev/sda1, use /dev/sda for grub, and boot either nixos or Ubuntu.
I can get the
boot.loader.grub.extraEntries to appear in the menu, but not to get a successful boot of the Ubuntu installation. Nixos boots fine, and I can boot the Ubuntu partition from a rescue CD. Does someone have something like this working, or can they direct me to additional sources - especially sources that might be good for other nixos newbie-type questions?