diff --git a/Makefile b/Makefile
index ac00def635..90c91e633e 100644
--- a/Makefile
+++ b/Makefile
@@ -23,6 +23,8 @@ GCS_TOOLS=\
 
 .PHONY: all always rootfs test
 
+.DEFAULT_GOAL := all
+
 all: out/initrd.img out/rootfs.tar.gz
 
 clean:
@@ -32,6 +34,12 @@ clean:
 test:
 	cd $(SRCROOT) && go test -v ./internal/guest/...
 
+rootfs: out/rootfs.vhd
+
+out/rootfs.vhd: out/rootfs.tar.gz bin/cmd/tar2ext4
+	gzip -f -d ./out/rootfs.tar.gz
+	bin/cmd/tar2ext4 -vhd -i ./out/rootfs.tar -o $@
+
 out/delta.tar.gz: bin/init bin/vsockexec bin/cmd/gcs bin/cmd/gcstools Makefile
 	@mkdir -p out
 	rm -rf rootfs
@@ -60,6 +68,7 @@ out/initrd.img: $(BASE) out/delta.tar.gz $(SRCROOT)/hack/catcpio.sh
 
 -include deps/cmd/gcs.gomake
 -include deps/cmd/gcstools.gomake
+-include deps/cmd/tar2ext4.gomake
 
 # Implicit rule for includes that define Go targets.
 %.gomake: $(SRCROOT)/Makefile