Just for information…
One of the stoppers for the rollout of 2004 was it not working with Thunderbolt. I updated my ThinkPad on day one anyway, even though I used Thunderbolt and it ran reliably. It was only docking/undocking that could cause problems and I always shut down my laptop at the end of the day, before unplugging it.
Earlier this month, I received a Thunderbolt update from Lenovo and today I had to do some training and undocked and re-docked the laptop and there were no problems.