I am planning to change computer configuration from CD+Floppy to  one
IDE-CF adapter + CF Card

As I know no problem to run m0n0wall on this configuration.

Question is how to update m0n0wall with CF (when new versions will be
released)

I don't have *nix around me for update config.xml directly in image.

I am not sure IDE-CF adapter is really hot swappable.

If I shutdown router and start it with new m0n0wall on CF card - it run with
default config and I need to connect monitor for assign interfaces and  LAN
IP.  Can I use serial cable to connect my laptop and set it up?

Is there any other way to update m0n0wall without changing default settings?