5D firmware upgrade (left the lens attached)

Just upgraded the 5D firmware 1.1.0

I was about halfway through the installation, when I kept look at the camera and saying to myself I've done something differtent this time. I'm shore this is not the same set up when I last did the firmware upgraded.

Then it hit me, my 24-70 L lens was still attached. I let it complete the upgrade. Then check and used the camera with 24-70 L I did not see any ill effects so far.

Now the question why do we need to remove lens during firmware upgrades, the only idea I can think of is it may change firmware in the lens?

i left mine attached for 1.05 and 1.1

I just read through Canon's firmware update instructions (included on the page with v1.1.0) and I found nothing along those lines. Where did you hear / read / discover that it was important to do so before updating? Because, like pjsun, I have updated my 5D to version 1.0.5 and 1.1.0 with a lens attached both times with no problems.

I remember with 1.0.3 & 4 Canon Japan site instructions (pdf file) said to remove len before installing firmware. ill have to go back and reread 1.1.0 firmware (PDF file instructions again)

This is what the download page for 20D says

Neither instructions for 5D or 1D MKIIN mentions anything about removing the lens so maybe it was just an issue with 20D and 300D (I think remember the same note about 300D).

Hmm... that's very interesting. Looks like it was necessary for the XT and the 20Da as well. Perhaps it has something to do with a specific problem that the new firmware was addressing for the 20D? Like I said though, nothing exploded when I flashed my 5D recently with the lens on (knock on wood), so I would presume that this isn't necessary for this camera / firmware update.

there where problems with earlier 20D's, when flashing the firmware with a lens attached some of them would crash during the update.
the camera had to go into repair after that, so from then on Canon put up the warning about the lenses.