OK, if it is too quiet

[Luke-Jr]

If it's saying "Buffer I/O error on device hd*a*", then this is Linux 
speaking, not GRUB. If Trustix works and CentOS does not, that means there is 
probably either a bugfix in a newer version of Linux, or a regression, 
depending on which OS has a more recent version of Linux.

Try copying the kernel and modules from Trustix to the CentOS/Ubuntu system 
and see if it will boot. (assuming they're both similar versions; eg, both 
2.6)