I'm running 126.96.36.199 on an apu1d4 and accidentally set the BIOS redirection to com2. I've tried clearing the CMOS by shorting J5 for over a minute with the power disconnected, but that doesn't seem to undo it. I also have an lpc.1a and can get to its BIOS menu with no problem, but it doesn't seem to have an option for resetting the onboard settings (at least not that I can find). What options do I have for getting the BIOS back onto com1, aside from hacking together a serial line to fit the com2 header?
Resetting CMOS won't work as these settings aren't saved there, they are written to flash memory. If you can boot into system you can re-flash the firmware, otherwise you can use external programmer (but connecting to COM2 header might be easier/cheaper). Flashing resets the configuration. Remember to change other options afterwards, if needed.
If you can boot into system you can re-flash the firmware
Thanks! The good news is that this worked (I had a viable OpenBSD 6.5 rootfs with flashrom already installed so was easy enough to try). Bad news is I'm pretty sure I had "BIOS write protect" enabled and wasn't hampered by it (what's it for if not preventing mainboard firmware reinstallation?).