Serial speed for boot device selection prompt

[Sean Bruno]

>> If you want serial capability in boot0, you should set
>> BOOT_COMCONSOLE_SPEED=115200 in your make.conf.  After you do that,
>> you'll need to rebuild the boot blocks.  The procedure for doing that is
>> step 4 of Section 24.6.5.2 in the Handbook:
>>
>> http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/serialconsole-setup.html
>>     
>
> The BIOS call that boot.S is using (int 0x14) only supports a maximum
> speed of 9600.  To get speeds greater that 9600, it needs to do the
> I/O itself.  There used to be a version floating around that did this.
> I have a extemely modified version that uses this method.  If you can't
> find a version that does this, let mw know and I'll see if I can cleanup
> what I have.
>
> Larry
>
>   
Thanks, that at least confirmed my theory while reviewing the assembly 
that boot.S was not capable of
more than 9600.

I'll look around first, but may request the code later.

Sean