My Raspberry Pi is running lots of useful services for me, and I depend on it quite heavily. But I had another hard-drive to install in it, greatly increasing the capacity.

This procedure is not as straight-forward as one would think, because my Pi boots from the hard-drive, and not the SD card (a procedure I would suppose to be more common, given how frequent it is to have a failing SD card in these devices). This is the resource I based the work on.

However, the line to change the file content from

dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 elevator=deadline root=/dev/mmcblk0p2 rootfstype=ext4 fsck.repair=yes rootwait

can be a bit misleading; at least my Raspbian didn't have that at all. So I just copied the final form of the expected result, substituing the correct dev entry.