If you are booting to your evox dash, then your chip is definatly working.
you can run the disk from the evox dash, but you can't boot it? Try the disks in your buddies xbox. If they work there, then you know it isn't the disks.
I am thinking too posibilities... Perhaps the disks are burned wrong (check with your buddies xbox)
Or the drive is having a hard time reading the disks. When you boot, it is timing out, but when you load from the dashboard, it takes a little longer but finaly loads successfully. If your buddie will let you, try his drive & if the problem goes away, then it is a drive isue.
Hope this helps, it is kind of a stab in the dark...