300mm f 2.8 mk2 firmware update

Took my 300mm f 2.8 mk2 into the Canon "authorised" service centre in Glasgow to have the firmware update done this morning. Spoke on the phone earlier this week and they said they could do it. I asked if I should plug it into my 1D MK4 and they said it might be a good idea. Got there this morning and was told I would need a 5D MK 3 or 1D X for them to be able to do it

So my next question is do I need the firmware update if I don't have any of these cameras, or should the service technician have been able to do it with some other device?

Thanks

I believe there is nothing to do with lens firmware update to the body you use. The update is to improve af performance. You only need 5d3 or 1dx just to verify the lens firmware. Currently only those 2 bodies can see firmware on the lens. So canon center should be able to do it with their cameras. Im planning to send mine too, and i will only send the lens not with my 5d3

And I also believe in the future, when they release new firmware and available on their website, you need 5D3 or 1DX in order to update the firmware by yourself

I had a 1.4x III TC that had to be sent to Canon to get the firmware adjusted/updated because it would not AF with my 400 f/5.6 on my 5D3... They said I could not do it myself, which I found weird considering they did it for the pancake. Fedex should be here any time now with it back from NJ to see if it fixed my issue. (All it would do is hunt back and forth).

I guess for now we can only update the bodies by ourselves. Any lenses or TCs that need to be updated have to be sent to Canon ( I didn't know that pancake had firmware update, so its an exception) . But in the future when Canon allow us to do it by ourselves, I'm pretty sure we can only do it with 5D3 or 1DX for now

I sent out my lens yesterday for a firmware update and to get the lens hood replaced(it was slightly loose).

I don't think the lenses will need to be updated very often, but it would be nice if it could be done at home like it can be with the bodies.