diff --git a/stand/i386/boot0/Makefile b/stand/i386/boot0/Makefile
index 5e82d7b6ae67..83eee46dfd11 100644
--- a/stand/i386/boot0/Makefile
+++ b/stand/i386/boot0/Makefile
@@ -1,87 +1,87 @@
 # $FreeBSD$
 
 PROG?=	boot0
 STRIP=
 BINMODE=${NOBINMODE}
 SRCS=	${PROG}.S
 
 # Additional options that you can specify with make OPTS="..."
 # (these only apply to boot0.S)
 #
 #	-DVOLUME_SERIAL	support volume serial number (NT, XP, Vista)
 #	-DSIO		do I/O using COM1:
 #	-DPXE		fallback to INT18/PXE with F6
 #	-DCHECK_DRIVE	enable checking drive number
 #	-DONLY_F_KEYS	accept only Fx keys in console
 #	-DTEST		print drive number on entry
 #
 OPTS ?= -DVOLUME_SERIAL -DPXE
 CFLAGS += ${OPTS}
 
 # Flags used in the boot0.S code:
 #   0x0f	all valid partitions enabled.
 #   0x80	'packet', use BIOS EDD (LBA) extensions instead of CHS
 #		to read from disk. boot0.S does not check that the extensions
 #		are supported, but all modern BIOSes should have them.
 #   0x40	'noupdate', disable writing boot0 back to disk so that
 #		the current selection is not preserved across reboots.
 #   0x20	'setdrv', override the drive number supplied by the bios
 #		with the one in the boot sector.
 
 # Default boot flags:
 BOOT_BOOT0_FLAGS?=	0x8f
 
 # The number of timer ticks to wait for a keypress before assuming the default
 # selection.  Since there are 18.2 ticks per second, the default value of
 # 0xb6 (182d) corresponds to 10 seconds.
 BOOT_BOOT0_TICKS?=	0xb6
 
 # The BIOS loads boot0 to the hardcoded address 0x7c00.  boot0 copies
 # itself to this alternate base address before continuing execution so
 # that next level boot blocks can be loaded at the 0x7c00 address they
 # expect.
 ORG=	0x600
 
 # Comm settings for boot0sio.
 #
 # boot0sio uses BIOS INT $0x14 for serial ports, we can only support these
 # baudrates due to INT14's limited interface. In addition, if
 # BOOT_BOOT0_COMCONSOLE_SPEED=0, then the baud rate and frame format will remain
 # unchanged. Some BIOSes initialize the serial ports to 115200, and this may
 # allow boot0sio access at that rate if so.
 #
 # Bit(s) Description
 # 7-5    data rate (110,150,300,600,1200,2400,4800,9600 bps)
 # 4-3    parity (00 or 10 = none, 01 = odd, 11 = even)
 # 2      stop bits (set = 2, clear = 1)
 # 1-0    data bits (00 = 5, 01 = 6, 10 = 7, 11 = 8)
 .if !defined(BOOT_BOOT0_COMCONSOLE_SPEED)
-BOOT_COMCONSOLE_SPEED?=	9600
+BOOT_COMCONSOLE_SPEED?=	9600	# BIOS interfaces do not support higher rates.
 .if ${BOOT_COMCONSOLE_SPEED} == 9600
 BOOT_BOOT0_COMCONSOLE_SPEED=	"7 << 5 + 3"
 .elif ${BOOT_COMCONSOLE_SPEED} == 4800
 BOOT_BOOT0_COMCONSOLE_SPEED=	"6 << 5 + 3"
 .elif ${BOOT_COMCONSOLE_SPEED} == 2400
 BOOT_BOOT0_COMCONSOLE_SPEED=	"5 << 5 + 3"
 .elif ${BOOT_COMCONSOLE_SPEED} == 1200
 BOOT_BOOT0_COMCONSOLE_SPEED=	"4 << 5 + 3"
 .elif ${BOOT_COMCONSOLE_SPEED} == 600
 BOOT_BOOT0_COMCONSOLE_SPEED=	"3 << 5 + 3"
 .elif ${BOOT_COMCONSOLE_SPEED} == 300
 BOOT_BOOT0_COMCONSOLE_SPEED=	"2 << 5 + 3"
 .elif ${BOOT_COMCONSOLE_SPEED} == 150
 BOOT_BOOT0_COMCONSOLE_SPEED=	"1 << 5 + 3"
 .elif ${BOOT_COMCONSOLE_SPEED} == 110
 BOOT_BOOT0_COMCONSOLE_SPEED=	"0 << 5 + 3"
 .else
 BOOT_BOOT0_COMCONSOLE_SPEED=	"7 << 5 + 3"
 .endif
 .endif
 
 CFLAGS+=-DFLAGS=${BOOT_BOOT0_FLAGS} \
 	-DTICKS=${BOOT_BOOT0_TICKS} \
 	-DCOMSPEED=${BOOT_BOOT0_COMCONSOLE_SPEED}
 
 LDFLAGS+=${LDFLAGS_BIN}
 
 .include <bsd.prog.mk>