Bear in mind that Upstart would have to be the initramfs /init just as its the real system /sbin/init - it has to be PID 1
One of the main pre-requisites for this is state passing; so that the upstart in the initramfs would be able to re-exec itself once the root is mounted and then pass its state to the new instance
Bear in mind that Upstart would have to be the initramfs /init just as its the real system /sbin/init - it has to be PID 1
One of the main pre-requisites for this is state passing; so that the upstart in the initramfs would be able to re-exec itself once the root is mounted and then pass its state to the new instance