@rondarius and all
Thank you all for your messages.
I must point out that I am also a confirmed Linux user and that I've been using ADB (and fastboot) for quite a while now. I'm sure, however, that I still have a lot to learn (the more I know, the more I can measure the extent of my ignorance).
I know these manips pretty well (those described in the Rondarius's post) because I've already practiced them quite a few times. And thanks for the link to the official stock Rom; I compared the checksum with what I've already downloaded and they are identical. But, you're right, you should always retrieve the data from the sources without going through an intermediary.
But my question is not about the procedure to be applied to flash the phone. What worries me is that apparently the partitioning of this Nexus 4 has been modified; and I fear possible problems when flashing the official rom stock without having made certain prior arrangements. I had a bad experience with a Nexus 5 that is currently bricked (I'm not desperate to bring it back to life...).
Do you think that flashing the google Rom will restore the original partitioning?