Disable GRUB serial communications ?

[Vilius Mockūnas]

Hello,

I have two linux boxes A and B. Each of them have serial ports (ttyS0 on both) and these ports are connected using null modem serial cable. "A" box is always on and it has getty process on its ttyS0 (I need this getty for serial communication). If I reboot box B, it doesn't boot default entry - just displays grub os select table. After some investigation I realized that getty process on A sends some data to grub on B while it's booting and grub behaves the same way as if some key is pressed during timeout period - it doesn't boot default and waits for interactive user response. I need to reboot B remotely so its no good for me. (disabling getty on A solves the problem, but I need that getty).  

Is it possible to disable any grub serial communications to solve my problem ?

thanks
Vilius