Oddball: Last time it resulted in a bricked router for whatever reason and no internet for four days. My flatmates wont risk it and they shouldn't have to, however small that risk is. I shouldn't be penalized for a fault in Orcon's mandatory hardware.
I have upgraded literally thousands of modems. Somewhere around 2% require a reboot after the operation. Perhaps two or three out of a thousand require another modem sent out, and in most cases it is due to power interruption during the upgrade. We upgrade them in the field routinely, as they are managed devices.
There are no security changes from the build which is compatible with Teamspeak to the latest build, the changes made were to support 100Mbps fibre at line speed. For ADSL and 30/10 UFB there is no difference at all between the firmwares.
Nevertheless I will see if we can do anything to help you out, without remotely downgrading your modem. Stay tuned.