Now I get it - systemd is now the default and to boot into upstart you need an init= command. I guess the $vt_handoff is new too.
This would be default systemd:
Code:
menuentry "Vivid Vervet 15.04 (devel branch)" {
set root=(hd0,5)
linux /vmlinuz root=/dev/sda5 ro quiet splash $vt_handoff
initrd /initrd.img
}
and this would be for upstart:
Code:
menuentry "Vivid Vervet 15.04 Upstart (devel branch)" {
set root=(hd0,5)
linux /vmlinuz root=/dev/sda5 ro quiet splash $vt_handoff init=/sbin/upstart
initrd /initrd.img
}
Thank you very much zika for bringing this to my attention.