can't boot from xpenoboot dsm 5.1

[treesrus]

Hi,

 

I've been using Nanoboot DSM 5.0 for a long time and it has worked fine for me. I decided to upgrade to xpenoboot 5.1. I created a new usb boot drive using the image the same way with win32diskimg. However, my system will not boot from the xpenoboot 5.1 thumbdrive. I tried the xpenoboot 5.1 thumbdrive on another system and it does boot. However, it will not boot in my server.

 

What is different between the nanoboot dsm 5.0 boot process than the xpenboot 5.1 boot process that would make my system not work with it?

 

asus m3a76-cm motherboard.

 

thanks!