Dell 6430U doesn’t play nice with Nokia E7

From time to time I check if my devices have a newer firmware available and then I make a round of updates.
While the un-branded Lumia 800 is still waiting for the availability of WP 7.8 I’ve found that finally the 3-branded E7 had belle refresh available so I started the upgrade process using the 6430u.

The full backup worked perfectly, but the update process failed a couple of time with errors pointing to the USB connection.
I believed this was because the cable (Nokia original) was connected using a hub so I connected directly to the notebook port only to find out that it was not working even this way.
As in the recent past I already had a major issue with the USB connector of the E7 I started to worry.

Having more than one computer at home I went to another one (an Acer 7750G that I use as a desktop replacement) and tried again with success.

I can’t tell if the problem is with the 6430U (drivers and bios are updated) or with the E7, but sure enough this is not something I liked.