stop "dmesg.boot" from being overwritten on each boot-up

I have a problem loading the 1915ms.ko module. I booted up and used the
"-v" option to get a detailed printout of what was happening. I copied
hat file to my home directory. I started the system again, but I set
the 1915ms.ko module to load. As usual, it froze the system. I then
rebooted into single user and made the necessary corrections. After
rebooting again, the contents of the dmesg.boot file were overwritten.

I want to get a copy of what happens when the system locks up while
booting with the i915ms.ko module. Is there any setting I can use to
stop overwriting that file or perhaps append the output to it?

Thanks!