I just created an IPFire clone on my testbed vm system and followed the instructions in the link from @cfusco. I successfully changed the root password so the process works.
Minor things to note.
The article says " Using your arrow keys once again, scroll down a bit until you see a line that begins with linux /boot/vmlinuz..." In the IPFire case the line starts with linux /vmlinuz
After running exec /sbin/init IPFire boots but then seems to stop. If you press the Return key then the console login prompt comes up.
Very well done @cfusco excellent solution and as you say then running setup the wui password can also be changed and also the network format and IP address and Domain name that was used can be found.