We have a few machines with console redirection in the bios. We access these with minicom.
To enter the bios, we've found that the VT100 escape sequences work.
To send F1, enter ESC O P, the capitalization on the O and P are essential.
Other codes that are known to work:
F12 comes through unharmed, so to get the boot menu on most machines, we just type F12 directly.