Before attempting to flash a router with openwrt, I like to jtag it so I can dump and restore the flash if it all goes horribly wrong. Unlike the the serial console, the jtag connections on the BT voyager 2091 aren't obvious - and unlike the previous bcm6348 boards I've jtag'd, someone hasn't already documented them.
more here...............http://www.sodnpoo.com/posts.xml/bt_voyager_2091_jtag.xml
more here...............http://www.sodnpoo.com/posts.xml/bt_voyager_2091_jtag.xml