bouyer@antioche.lip6.fr said:
>  	pvbcopy((void *)(0x400 + 0x75), &nhd, 1);
> +	nhd &= 0xff; 

pvbcopy() copies 1 byte out of the BIOS data area, so
the upper 3 bytes of "nhd" remain uninitialized.
The correct solution is to either declare "nhd" as
char or zero it before.

best regards
Matthias