Motorola Cable Modem DOS

I've found it trivial to crash the Motorola Surfboard 4200 Cable modem, as installed default by AT&T Broadband Internet. The modem acts as a bridge, but also has an internal RFC1918 IP address 192.168.100.1. Simply nmap'ing the cable user's IP address, ie: nmap -sS -p 1-1024 12.x.x.x will cause i...