diff --git a/sys/boot/efi/libefi/Makefile b/sys/boot/efi/libefi/Makefile
index 76ed0ca..2d1d39d 100644
--- a/sys/boot/efi/libefi/Makefile
+++ b/sys/boot/efi/libefi/Makefile
@@ -17,7 +17,4 @@ CFLAGS+= -I${.CURDIR}/../../../../lib/libstand
 CFLAGS+= -I${.CURDIR}/../../common
 
  
-# Suppress warning from clang for FreeBSD %b and %D formats
-CFLAGS+= -fformat-extensions
-
 .include <bsd.lib.mk>
diff --git a/sys/boot/i386/libi386/Makefile b/sys/boot/i386/libi386/Makefile
index d714c74..a5cfa3c 100644
--- a/sys/boot/i386/libi386/Makefile
+++ b/sys/boot/i386/libi386/Makefile
@@ -52,9 +52,6 @@ CFLAGS+=	-I${.CURDIR}/../../common -I${.CURDIR}/../common \
 # the location of libstand
 CFLAGS+=	-I${.CURDIR}/../../../../lib/libstand/
 
-# Suppress warning from clang for FreeBSD %b and %D formats
-CFLAGS+= -fformat-extensions
-
 .if ${MACHINE_CPUARCH} == "amd64"
 CLEANFILES+=	machine
 machine: