Does any one have a config register table that can upload? I thought I knew most of them, but then 0x2100 came up in my Boson practise test and I didn't know this one.
The 0x2100 tells your router to boot into ROM monitor mode, where you have to do most things manually. Usually when you need to enter ROM monitor mode something have gone bad and you need to fix something, like how the router/switch looks for IOS, Configuration files etc.
Conwyn have provided a good link for config registers:
It's very handy if you understand the technical information.