1. Harman Kardon Bco Update
2. Software Update Mac

Mar 12, 2012 - 6 min - Uploaded by Wes BeckwithThis video is done by Web Services DFW (for Bobcat Custom. Sep 17, 2016. If you own a Harman Kardon AVR1700 receiver that has locked up after displaying a BCO Update message, this fix may work for you. Connect your HK to your home network using an ethernet cable. Type the IP address for the HK in a new browser window or tab.

Harman Kardon Bco Update

Software Update Mac

I'm trying to extract firmware for the Harman Kardon AVR 1700, with the eventual goal of modifying it but mostly just for fun. (This is a networked receiver and it has a remote app that can be used to control the device. Unfortunately, it's horribly unreliable, and I'd much prefer to get shell access to the device and write some basic software to be able to control it remotely from my computer.)

There's a firmware update available here (EU version is numbered 170 but otherwise identical), which I installed recently. This is a fairly small file (~3MB unpacked), so I'm not sure whether it contains the full firmware or I'm just not used to the small size of embedded OS's. Binwalk unfortunately doesn't tell me anything useful about the structure of the file (the XML doc it finds is just a small fragment):

Nmap tells me it runs an OS that's shared across a number of receivers:

This led me to this post where someone is trying reverse engineer a Pioneer VSX-822 and can't identify the file type of the firmware image. I'm basically in the same boat I think, and the answers there suggest the firmware is encrypted.

Anyone have any ideas how to proceed? I'm quite new at fiddling with embedded systems, although I have a lot of coding experience (including some low-level OS dev and assembler). I don't have any hardware/electrical experience to speak of, so e.g. pulling the flash off the board and dumping it is probably more than I'm up for, unless that's simpler than it sounds and someone can point me to some clear instructions somewhere. Any help greatly appreciated!