diff --git a/stand/i386/pxeldr/Makefile b/stand/i386/pxeldr/Makefile
index 27f9a44cf21c..36d3d3ad878e 100644
--- a/stand/i386/pxeldr/Makefile
+++ b/stand/i386/pxeldr/Makefile
@@ -1,50 +1,58 @@
 
 .include <bsd.init.mk>
 
 PROG=	${LDR}
 INTERNALPROG=
 FILES=	${BOOT}
 MAN=	${BOOT}.8
 SRCS=	${LDR}.S
 CLEANFILES+= ${BOOT}
 
 BOOT=	pxeboot
 LDR=	pxeldr
 ORG=	0x7c00
 LOADER=	loader
 
 .if defined(BOOT_PXELDR_PROBE_KEYBOARD)
 CFLAGS+=-DPROBE_KEYBOARD
 .endif
 
 .if defined(BOOT_PXELDR_ALWAYS_SERIAL)
 CFLAGS+=-DALWAYS_SERIAL
 .endif
 
 CFLAGS+=-I${BOOTSRC}/i386/common
 
 .if defined(PXEBOOT_DEFAULT_INTERP)
 L=${PXEBOOT_DEFAULT_INTERP}
 .else
 L=${LOADER_DEFAULT_INTERP}
 .endif
 LOADERBIN= ${BOOTOBJ}/i386/loader_${L}/loader_${L}.bin
+# pxeboot runs in an environment where there's 500k or less of space available
+# due to space for packet buffers, network drivers, etc. While some environments
+# may have a bit more, the limit of 500,000 (488k) provides enough margin to
+# work in a huge array of environments. Larger values may work for specific
+# environments.
+PXEBOOTSIZE?=500000
 
 CLEANFILES+= ${BOOT}.tmp
 
 ${BOOT}: ${LDR} ${LOADER}
 	cat ${LDR} ${LOADER} > ${.TARGET}.tmp
 	${DD} if=${.TARGET}.tmp of=${.TARGET} bs=2048 conv=sync
 	rm ${.TARGET}.tmp
 
 LDFLAGS+=${LDFLAGS_BIN}
 
 CLEANFILES+= ${LOADER}
 
 # Note: pxeldr.S assumes a.out and will require changes for ELF if the output
 # format is changed to ELF.
 ${LOADER}: ${LOADERBIN} ${BTXLDR} ${BTXKERN}
+	@set -- `ls -l ${LOADERBIN}` ; x=$$((${PXEBOOTSIZE}-$$5)); \
+	    echo "$$x bytes available"; test $$x -ge 0
 	btxld -v -f aout -e ${LOADER_ADDRESS} -o ${.TARGET} -l ${BTXLDR} \
 	    -b ${BTXKERN} ${LOADERBIN}
 
 .include <bsd.prog.mk>