Grub serial console does not work

[jimmi]

Hi,

I'm using since several years the serial console to get the grub menu from a 
headless PC, that I configured following the instruction of the
Remote Serial Console HOWTO [1].  I'm now replacing the machine with a mini-itx 
assembled with an Intel D201GLY2 board [2] on which I installed a Debian 
stable. Using the same configuration the grub menu ("Press any key to 
continue") appears only on the local monitor, while the output on the serial 
console starts working only when the kernel boots off.

Any idea which test may I do to understand where the problem is?

Thanks in advance.
Jimmi

[1]http://tldp.org/HOWTO/Remote-Serial-Console-HOWTO/configure-kernel-grub.html
[2]http://www.intel.com/products/motherboard/d201gly2/