From the Wiki entry for the WR850G, one may deduce that all hardware versions are equally supported by OpenWRT.
Searching the forum, I learned that there may be issues with older hw's though - I've got a v1 (the one with the two-part power cord).
What's the current status, and is there a way to convert existing 'config.bin' backup files to 'nvram show'-output style so I can
check the previous settings?
Since the v1 is based on bcm94710dev (or even 4702) I think it has to be handled separately - in particular the 'default firmware
setting' differ from v2 and later. I could not find this in the OpenWRT code (yet)... could someone in the know please take my hand?
Thanks, S.

I've installed OpenWRT to WR850 v1 with no issues.

Besides failsafe mode not working and the reset button not working entirely properly, and the ports being ordered contrary to their labeling.  But that is all v2.  Maybe v1 does not have those problems.

The v1 has these issues, but it is nothing major.

I have bricked several V1 units trying to get them into client mode. They seem ok until I put them into client mode using the client mode howto. No serial port so I guess I'm out of luck. V2 units seem fine.

Everything works fine for me on a v2 as well.. Only stuff missing is the wireless light on that, but found the way to fix it, just I don't have time to push it to SVN right now.

The WR850 port layout is different than the Client Mode HOWTO is suggesting:

#Based on "routed client mode" ( http://wiki.openwrt.org/ClientModeHowto ):

root@OpenWrt:~# rm /etc/init.d/S50dnsmasq
root@OpenWrt:~# cp /rom/etc/init.d/S50dnsmasq /etc/init.d/
root@OpenWrt:~# chmod -x /etc/init.d/S50dnsmasq

root@OpenWrt:~# nvram set wl0_mode=sta
root@OpenWrt:~# nvram set wl0_ssid=test
root@OpenWrt:~# nvram set wan_ifname=eth1
root@OpenWrt:~# nvram set lan_ifname=br0
root@OpenWrt:~# nvram get lan_ifnames
vlan0 eth1 wds0.2 wds0.3 wds0.4 wds0.5
root@OpenWrt:~# nvram set lan_ifnames="vlan0 wds0.2 wds0.3 wds0.4 wds0.5"
root@OpenWrt:~# nvram commit