diff --git a/hello-stratum.morph b/hello-stratum.morph
index 73ed482..475fe0f 100644
--- a/hello-stratum.morph
+++ b/hello-stratum.morph
@@ -2,7 +2,8 @@ chunks:
 - build-depends: []
   build-mode: test
   name: hello
-  ref: master
+  ref: newbranch
   repo: test:hello
+  unpetrify-ref: master
 kind: stratum
 name: hello-stratum
diff --git a/hello-system.morph b/hello-system.morph
index 721473c..1537f53 100644
--- a/hello-system.morph
+++ b/hello-system.morph
@@ -3,9 +3,9 @@ kind: system
 name: hello-system
 strata:
 - morph: hello-stratum
-  ref: master
+  ref: newbranch
   repo: test:morphs
+  unpetrify-ref: master
 - morph: xyzzy-stratum
   ref: master
   repo: test:morphs
-system-kind: rootfs-tarball
diff --git a/xyzzy-stratum.morph b/xyzzy-stratum.morph
index e302037..bcf5b57 100644
--- a/xyzzy-stratum.morph
+++ b/xyzzy-stratum.morph
@@ -1,11 +1,13 @@
 build-depends:
 - morph: hello-stratum
-  ref: master
+  ref: newbranch
   repo: test:morphs
+  unpetrify-ref: master
 chunks:
 - build-depends: []
   name: hello
-  ref: master
+  ref: newbranch
   repo: test:hello
+  unpetrify-ref: master
 kind: stratum
 name: xyzzy-stratum