You said RC10 fixed the problem. But who repairs our RB1100? 
Netinstall doesn’t work for that devices anymore. Do you have any idea?
what serial output you get when booting 
try to boot in backup booter
RC9 did not permanently break your 1100, and if you can’t get Netinstall to work, you are doing something wrong. Netinstall is a function of RouterBOOT, which did not get touched when you installed RC9.
– Nathan