Wondering if anyone else has experienced this issue. I'm running a Tyan S5211 motherboard in two different machines. The board works fine, except I can't reboot the machine. Using the restart switch on the case or sending a reboot command from any OS gives the same results. Instead of booting properly, it appears the system goes into a loop prior to putting out any video output. The only real clue I have is that it never makes it as far as the "60" code when doing its boot. It gets as far as code 49 and then restarts the process. I can get the server to boot by powering it down completely and starting it back up manually.
I also have this problem, but gave up on fixing it about a year ago until I was off the W7 beta. Now I'm at it again and looking for solutions.
I am using the board in a Supermicro case (yes, this turned out a bit problematic).
The system also boots up on its thrid attempt every time - sound familiar? I can power-on, and it will shut off almost immediately after I hear that all devices have powered up. If I find a fix, I'll post it here.