Greetings; I am playing around with Hyper-V 2012 RTM (build: 9200 final).
The it appears that it is not possible to boot with jemmex or emm386 driver. It does work the xmgr though.
The error message being reported is: ""System memory found at e000-efff, region might be in use"
If there is a jump starter on how to debug the boot loader I would be willing to do an initial investigation