diff --git a/lib/libstand/Makefile b/lib/libstand/Makefile
index a06cf514cd02..c2fc7a4f7091 100644
--- a/lib/libstand/Makefile
+++ b/lib/libstand/Makefile
@@ -22,6 +22,9 @@ CFLAGS+=	-mno-mmx -mno-3dnow -mno-sse -mno-sse2
 .if ${MACHINE_ARCH} == "i386"
 CFLAGS+=	-mno-sse3
 .endif
+.if ${MACHINE} == "pc98"
+CFLAGS+=	-Os
+.endif
 .if ${MACHINE_ARCH} == "powerpc"
 CFLAGS+=	-msoft-float -D_STANDALONE
 .endif
diff --git a/sys/boot/ficl/Makefile b/sys/boot/ficl/Makefile
index a1cc45b4202f..f8f629298f7e 100644
--- a/sys/boot/ficl/Makefile
+++ b/sys/boot/ficl/Makefile
@@ -18,7 +18,7 @@ CFLAGS+=	-mno-sse3
 CFLAGS+=	-msoft-float
 .endif
 .if ${MACHINE} == "pc98"
-CFLAGS+=	-DPC98
+CFLAGS+=	-Os -DPC98
 .endif
 .if HAVE_PNP
 CFLAGS+=	-DHAVE_PNP
diff --git a/sys/boot/pc98/Makefile.inc b/sys/boot/pc98/Makefile.inc
index 379dae33f4c8..5bdddeeaa5c1 100644
--- a/sys/boot/pc98/Makefile.inc
+++ b/sys/boot/pc98/Makefile.inc
@@ -6,7 +6,8 @@ BINDIR?=	/boot
 
 LOADER_ADDRESS?=0x100000
 CFLAGS+=	-ffreestanding -mpreferred-stack-boundary=2 \
-		-mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3
+		-mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3 \
+		-Os
 LDFLAGS+=	-nostdlib
 
 # BTX components