Hi all...i have continiously facing the thing that your clock setting may changed when your debian box reboot.

Here is the simple solution to get hold of it......

First Check using

hwclock

Output:

select() to /dev/rtc to wait for clock tick timed out 

So Lets Do the Trick.... 
mv /sbin/hwclock /sbin/hwclock.dist 
touch /sbin/hwclock vi /sbin/hwclock

add the following:

#!/bin/sh /sbin/hw
clock.dist --directisa "$@"
save & exit

chmod +x /sbin/hwclock

vi /etc/default/rcS

append the following line

HWCLOCKPARS="--directisa"

save and exit

Thats all...done.