diff --git a/sys/stand/efiboot/Makefile.efiboot b/sys/stand/efiboot/Makefile.efiboot
index b5e4308774dc..e5ed8d673fdf 100644
--- a/sys/stand/efiboot/Makefile.efiboot
+++ b/sys/stand/efiboot/Makefile.efiboot
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile.efiboot,v 1.10 2020/01/25 11:24:20 jmcneill Exp $
+# $NetBSD: Makefile.efiboot,v 1.11 2020/04/01 10:45:44 tnn Exp $
 
 S=		${.CURDIR}/../../..
 
@@ -87,6 +87,11 @@ CPPFLAGS+= -DLIBSA_ENABLE_LS_OP
 #CPPFLAGS+= -DRARP_DEBUG
 #CPPFLAGS+= -DRPC_DEBUG
 
+# Follow the suit of Makefile.kern.inc; needed for the lfs64 union
+# accessors -- they don't actually dereference the resulting pointer,
+# just use it for type-checking.
+CWARNFLAGS.clang+=	-Wno-error=address-of-packed-member
+
 SAMISCCPPFLAGS+= -DLIBSA_PRINTF_LONGLONG_SUPPORT
 SAMISCCPPFLAGS+= -DLIBSA_PRINTF_WIDTH_SUPPORT
 SAMISCCPPFLAGS+= -D"cdb2devb(bno)=(bno)"