Surprisingly easy as it happens!
Firstly boot your device and get to su command line ([ Ctrl ] [ Alt ] [ F2 ]), log in as chronos and then
Then pop in the wireless dongle and review the contents of dmesg.
You should see something along the lines of the following:
rtl8192cu: Loading firmware rtlwifi/rtl8192cufw.bin rtlwifi: Firmware rtlwifi/rtl8192cufw.bin not available
In order to remedy this, firstly mount the OS read/write:
mount -o remount, rw /
Then create the directory structure and cd into it, and download the bin file
mkdir /lib/firmware/rtlwifi cd /lib/firmware/rtlwifi/ wget http://chromium.arnoldthebat.co.uk/files/fw/lib/firmware/rtlwifi/rtl8192cufw.bin
Remove the dongle and reinsert. Lights on the dongle will now illuminate and you ‘should’ be able to connect to a wireless network! The version I tested against would not scan the network so I needed to add the wireless network manually. Reboot will remember the change so all should be good from that point on.
Any dev server updates will more than likely undo any of the above so please bear that in mind.
Usual caveats around none of this ever working etc.