I tried to perform a headless install on an Intel based computer by connecting a DEC VT510 serial terminal to COM1 (null modem cable, and H8571-J [mmj to DB9] connector) and typing 'linux serial' from a temporaily installed keyboard on the PC. I ended up having to install a video card, monitor, keyboard and mouse on the computer to get 6.1 installed. Having the video card an monitor installed I agian typed in 'linux serial' and it proceeded with the normal install without transfering control to the serial terminal. Once the installation was complete I opened up a getty on COM1 and the serial terminal worked fine. inittab entry S0:2345:respawn:/sbin/getty ttyS0 DT9600 vt100 reread inittab file without rebooting telinit q If you try the same proceedure in 6.0 it works. You shouldn't have to install a video card, monitor, keyboard and mouse to install linux if it is going to be used as a file server/firewall/router. Most of those computers are remotely administered and those devices can present a security risk especially if the computer is located in a non secure area.
We are aware of bugs with the serial installs on intel workstations. It will definitely be back to its 6.0-behavior in the next release.
There needs to be some sort of prompt at the serial terminal during the install process so you don't have to connect a keyboard to the PC during the install. The SPARC install is a good example.
With the latest installer, you can type "linux console=ttyS0" at the syslinux prompt and start a serial installation (of course, ttyS1, S2, etc. work as well)