Index: head/stand/i386/boot2/Makefile
===================================================================
--- head/stand/i386/boot2/Makefile
+++ head/stand/i386/boot2/Makefile
@@ -66,7 +66,7 @@
 boot2: boot2.ld
 	@set -- `ls -l ${.ALLSRC}`; x=$$((${BOOT2SIZE}-$$5)); \
 	    echo "$$x bytes available"; test $$x -ge 0
-	${DD} if=${.ALLSRC} of=${.TARGET} obs=${BOOT2SIZE} conv=osync
+	${DD} if=${.ALLSRC} of=${.TARGET} bs=${BOOT2SIZE} conv=sync
 
 boot2.ld: boot2.ldr boot2.bin ${BTXKERN}
 	btxld -v -E ${ORG2} -f bin -b ${BTXKERN} -l boot2.ldr \
Index: head/stand/i386/pxeldr/Makefile
===================================================================
--- head/stand/i386/pxeldr/Makefile
+++ head/stand/i386/pxeldr/Makefile
@@ -31,7 +31,7 @@
 
 ${BOOT}: ${LDR} ${LOADER}
 	cat ${LDR} ${LOADER} > ${.TARGET}.tmp
-	${DD} if=${.TARGET}.tmp of=${.TARGET} obs=2k conv=osync
+	${DD} if=${.TARGET}.tmp of=${.TARGET} bs=2048 conv=sync
 	rm ${.TARGET}.tmp
 
 LDFLAGS+=${LDFLAGS_BIN}
Index: head/stand/i386/zfsboot/Makefile
===================================================================
--- head/stand/i386/zfsboot/Makefile
+++ head/stand/i386/zfsboot/Makefile
@@ -62,7 +62,7 @@
 zfsboot2: zfsboot.ld
 	@set -- `ls -l ${.ALLSRC}`; x=$$((${BOOT2SIZE}-$$5)); \
 	    echo "$$x bytes available"; test $$x -ge 0
-	${DD} if=${.ALLSRC} of=${.TARGET} obs=${BOOT2SIZE} conv=osync
+	${DD} if=${.ALLSRC} of=${.TARGET} bs=${BOOT2SIZE} conv=sync
 
 zfsboot.ld: zfsboot.ldr zfsboot.bin ${BTXKERN}
 	btxld -v -E ${ORG2} -f bin -b ${BTXKERN} -l zfsboot.ldr \