I have a couple Duemilanoves and an Uno. Does the boot loader support a watchdog timer? If some Arduinos do and some don't, how can I tell?
Maybe I am missing something, but why would the bootloader have anything to do with the watchdog timer?
If the watch dog timer is set up with a time out value shorter then what the bootloaders time out period is, then the whole thing can get caught up in a tight loop never jumping back to the user sketch. I think Ladyada was the first to offer a modified bootloader that handled the WDT interrupt correctly. It's not clear which of the many version of 'official Arduino' bootloaders in the various IDE versions for the various processors supported are WDT safe or not. I'm pretty sure the latest UNO bootloader is WDT safe but not sure that is only with the bootloader being shipped but possibly not the one distributed with version 22? It's all been a bumpy ride, but solvable if you search around.
Could you write a sketch that tested an Arduino to see if it properly supported a WDT? Is so, how would you do it.
No the only way would be to enable the watchdog for a very short interrupt time. If the arduino is then bricked it's bootloader doesn't handle the watchdog correctly.