retrolefty:
I'm pretty sure the uno bootloader for the 328p handles WDT correctly. Probably you should try and figure out why you can't burn and run optiboot on your 328p chip rather then trying to add a function to your old bootloader.
Not sure why but the bootloader didn't like running at 8MHz, at least from the internal RC oscillator. I even posted a question some time ago but nobody seemed to be using those settings with optiboot.
And again why not just run your calibration function inside the setup function in your sketch?
This is how I'm running it right now. I just wondered if running the calibration tasks from the bootloader was something possible, mainly because I wanted to run them before comms start.
Thanks again!
Daniel.