Index: head/sys/boot/efi/boot1/Makefile
===================================================================
--- head/sys/boot/efi/boot1/Makefile	(revision 323260)
+++ head/sys/boot/efi/boot1/Makefile	(revision 323261)
@@ -1,154 +1,161 @@
 # $FreeBSD$
 
 MAN=
 
 .include <src.opts.mk>
 
 MK_SSP=		no
 
 PROG=		boot1.sym
 INTERNALPROG=
 WARNS?=		6
 
+# We implement a slightly non-standard %S in that it always takes a
+# CHAR16 that's common in UEFI-land instead of a wchar_t. This only
+# seems to matter on arm64 where wchar_t defaults to an int instead
+# of a short. There's no good cast to use here so just ignore the
+# warnings for now.
+CWARNFLAGS.boot1.c+=	-Wno-format
+
 # Disable warnings that are currently incompatible with the zfs boot code
 CWARNFLAGS.zfs_module.c += -Wno-array-bounds
 CWARNFLAGS.zfs_module.c += -Wno-cast-align
 CWARNFLAGS.zfs_module.c += -Wno-cast-qual
 CWARNFLAGS.zfs_module.c += -Wno-missing-prototypes
 CWARNFLAGS.zfs_module.c += -Wno-sign-compare
 CWARNFLAGS.zfs_module.c += -Wno-unused-parameter
 CWARNFLAGS.zfs_module.c += -Wno-unused-function
 CWARNFLAGS.skein.c += -Wno-cast-align
 .if ${COMPILER_TYPE} == "clang"
 CWARNFLAGS.skein.c += -Wno-missing-variable-declarations
 .else if ${COMPILER_TYPE} == "gcc"
 CWARNFLAGS.skein.c += -Wno-missing-declarations
 .endif
 
 # architecture-specific loader code
 SRCS=	boot1.c self_reloc.c start.S ufs_module.c
 .if ${MK_ZFS} != "no"
 SRCS+=		zfs_module.c
 SRCS+=		skein.c skein_block.c
 # Do not unroll skein loops, reduce code size
 CFLAGS+=	-DSKEIN_LOOP=111
 .PATH:		${.CURDIR}/../../../crypto/skein
 .endif
 
 .if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} > 40201
 CWARNFLAGS.self_reloc.c+=	-Wno-error=maybe-uninitialized
 .endif
 
 CFLAGS+=	-I.
 CFLAGS+=	-I${.CURDIR}/../include
 CFLAGS+=	-I${.CURDIR}/../include/${MACHINE}
 CFLAGS+=	-I${.CURDIR}/../../../contrib/dev/acpica/include
 CFLAGS+=	-I${.CURDIR}/../../..
 CFLAGS+=	-DEFI_UFS_BOOT
 .ifdef(EFI_DEBUG)
 CFLAGS+=	-DEFI_DEBUG
 .endif
 
 .if ${MK_ZFS} != "no"
 CFLAGS+=	-I${.CURDIR}/../../zfs/
 CFLAGS+=	-I${.CURDIR}/../../../cddl/boot/zfs/
 CFLAGS+=	-I${.CURDIR}/../../../crypto/skein
 CFLAGS+=	-DEFI_ZFS_BOOT
 .endif
 
 # Always add MI sources and REGULAR efi loader bits
 .PATH:		${.CURDIR}/../loader/arch/${MACHINE}
 .PATH:		${.CURDIR}/../loader
 .PATH:		${.CURDIR}/../../common
 CFLAGS+=	-I${.CURDIR}/../../common
 
 FILES=	boot1.efi boot1.efifat
 FILESMODE_boot1.efi=	${BINMODE}
 
 LDSCRIPT=	${.CURDIR}/../loader/arch/${MACHINE}/ldscript.${MACHINE}
 LDFLAGS+=	-Wl,-T${LDSCRIPT},-Bsymbolic,-znotext -shared
 
 .if ${MACHINE_CPUARCH} == "aarch64"
 CFLAGS+=	-mgeneral-regs-only
 .endif
 .if ${MACHINE_CPUARCH} == "amd64" || ${MACHINE_CPUARCH} == "i386"
 CFLAGS+=	-fPIC
 LDFLAGS+=	-Wl,-znocombreloc
 .endif
 
 LIBEFI=		${.OBJDIR}/../libefi/libefi.a
 
 #
 # Add libstand for the runtime functions used by the compiler - for example
 # __aeabi_* (arm) or __divdi3 (i386).
 # as well as required string and memory functions for all platforms.
 #
 DPADD+=		${LIBEFI} ${LIBSTAND}
 LDADD+=		${LIBEFI} -lstand
 
 DPADD+=		${LDSCRIPT}
 
 NM?=		nm
 OBJCOPY?=	objcopy
 
 .if ${MACHINE_CPUARCH} == "amd64"
 EFI_TARGET=	efi-app-x86_64
 .elif ${MACHINE_CPUARCH} == "i386"
 EFI_TARGET=	efi-app-ia32
 .else
 EFI_TARGET=	binary
 .endif
 
 # Arbitrarily set the PE/COFF header timestamps to 1 Jan 2016 00:00:00
 # for build reproducibility.
 SOURCE_DATE_EPOCH?=1451606400
 boot1.efi: ${PROG}
 	if ${NM} ${.ALLSRC} | grep ' U '; then \
 		echo "Undefined symbols in ${.ALLSRC}"; \
 		exit 1; \
 	fi
 	SOURCE_DATE_EPOCH=${SOURCE_DATE_EPOCH} \
 	${OBJCOPY} -j .peheader -j .text -j .sdata -j .data \
 		-j .dynamic -j .dynsym -j .rel.dyn \
 		-j .rela.dyn -j .reloc -j .eh_frame \
 		--output-target=${EFI_TARGET} ${.ALLSRC} ${.TARGET}
 
 boot1.o: ${.CURDIR}/../../common/ufsread.c
 
 # The following inserts our objects into a template FAT file system
 # created by generate-fat.sh
 
 .include "${.CURDIR}/Makefile.fat"
 BOOT1_MAXSIZE?=	131072
 
 boot1.efifat: boot1.efi
 	@set -- `ls -l ${.ALLSRC}`; \
 	x=$$(($$5-${BOOT1_MAXSIZE})); \
 	if [ $$x -ge 0 ]; then \
 	    echo "boot1 $$x bytes too large; regenerate FAT templates?" >&2 ;\
 	    exit 1; \
 	fi
 	echo ${.OBJDIR}
 	uudecode ${.CURDIR}/fat-${MACHINE}.tmpl.bz2.uu
 	mv fat-${MACHINE}.tmpl.bz2 ${.TARGET}.bz2
 	bzip2 -f -d ${.TARGET}.bz2
 	${DD} if=${.ALLSRC} of=${.TARGET} seek=${BOOT1_OFFSET} conv=notrunc
 
 CLEANFILES= boot1.efi boot1.efifat
 
 .include <bsd.prog.mk>
 
 beforedepend ${OBJS}: machine
 
 CLEANFILES+=   machine
 
 machine: .NOMETA
 	ln -sf ${.CURDIR}/../../../${MACHINE}/include machine
 
 .if ${MACHINE_CPUARCH} == "amd64" || ${MACHINE_CPUARCH} == "i386"
 beforedepend ${OBJS}: x86
 CLEANFILES+=   x86
 
 x86: .NOMETA
 	ln -sf ${.CURDIR}/../../../x86/include x86
 .endif