For anyone who has found this thread because their AVR 1700 is stuck in BCO Update mode, I wanted to post a the solution that worked for me this morning:
Connect your AVR 1700 to your home network. For me, this meant temporarily moving my cable modem and wireless router into the living room and connecting the receiver to my router with an ethernet cable.
Using your computer, determine the IP address of the AVR 1700 on your local network. You can do this by logging into your wireless router's web interface, or by using a utility like this one: http://www.nirsoft.n..rk_watcher.html
Type the IP address of your AVR 1700 into a web browser on your computer (it should like this: 192.168.1.xxx, with the last three digits based on your individual network). If done correctly, you will be looking at the Harman Kardon web interface for the receiver.
Click the Choose File button and choose any random file on your computer. I picked a small txt file. Now click the Upload button. Dont' worry about what file you choose. The operation will fail, but you will have jolted the receiver out of update mode.
You're done. BCO Update message should disappear, and life is good again!
I hope this helps!