Unable to boot to internal or serial console

[Teo De Las Heras]

I read through serial communication section in the FreeBSD handbook this
morning. I was able to configure the serial on one of my machines through
the following steps:
1. Edit /etc/ttys
a. ttyd0 "ttyd0 "/usr/libexec/getty std.9600" vt100 on insecure
2. Edit /boot/loader.rc
b. In the very first line add set console="comconsole"

After doing this on the second machine and rebooting, I am not able to get
to the serial console, video console, or SSH.  There are not errors on the
screen, just a blinking curser after "FreeBSD/i386 bootstrap loader,
Revision 1.1"

How can I get back into the system?