diff --git a/Makefile.inc1 b/Makefile.inc1
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -1943,7 +1943,7 @@
 WSTAGEDIR?=	${OBJTOP}/worldstage
 KSTAGEDIR?=	${OBJTOP}/kernelstage
 REPODIR?=	${OBJROOT}repo
-PKG_FORMAT?=	txz
+PKG_FORMAT?=	tzst
 PKG_REPO_SIGNING_KEY?=	# empty
 PKG_OUTPUT_DIR?=	${PKG_VERSION}