The above advice directly mirrors my experience of loading new firmware to my HG612 a few weeks ago. It took me three goes to get the firmware loaded to mine, and the key was exactly as above - wait. The main issue I had was not waiting long enough at step 10 - it takes a surprisingly long time to load the new firmware and there is little in the way of a proper indication that it has completed, so as advised, just wait a long time to be sure.