diff --git a/src/cmd-build b/src/cmd-build
index d7766f66a0..a7488f1ecf 100755
--- a/src/cmd-build
+++ b/src/cmd-build
@@ -384,20 +384,21 @@ if [ "${commit}" == "${previous_commit}" ] && \
     fi
 else
     ostree_format=$(jq -r '.["ostree-format"]' < "${image_json}")
+    ostree_tarfile_path="${name}-${buildid}-ostree.${basearch}.ociarchive"
+    gitsrc=$(jq -r .git.origin < "${PWD}/coreos-assembler-config-git.json")
+    cmd=(ostree container encapsulate)
     case "${ostree_format}" in
-        null|oci)
-            ostree_tarfile_path="${name}-${buildid}-ostree.${basearch}.ociarchive"
-            gitsrc=$(jq -r .git.origin < "${PWD}/coreos-assembler-config-git.json")
-            runv rpm-ostree container-encapsulate --repo="${tmprepo}" \
-                --label="coreos-assembler.image-config-checksum=${image_config_checksum}" \
-                --label="coreos-assembler.image-input-checksum=${image_input_checksum}" \
-                --label="org.opencontainers.image.source=${gitsrc}" \
-                --label="org.opencontainers.image.revision=${config_gitrev}" \
-                --ref="${buildid}" \
-                oci-archive:"${ostree_tarfile_path}".tmp:latest
-            ;;
+        oci) ;;
+        oci-chunked) cmd=(rpm-ostree container-encapsulate) ;;
         *) fatal "Unknown ostree-format: ${ostree_format}"
     esac
+    runv "${cmd[@]}" --repo="${tmprepo}" \
+        --label="coreos-assembler.image-config-checksum=${image_config_checksum}" \
+        --label="coreos-assembler.image-input-checksum=${image_input_checksum}" \
+        --label="org.opencontainers.image.source=${gitsrc}" \
+        --label="org.opencontainers.image.revision=${config_gitrev}" \
+        --ref="${buildid}" \
+        oci-archive:"${ostree_tarfile_path}".tmp:latest
     /usr/lib/coreos-assembler/finalize-artifact "${ostree_tarfile_path}"{.tmp,}
     ostree_tarfile_sha256=$(sha256sum "${ostree_tarfile_path}" | awk '{print$1}')
 fi
diff --git a/src/image-default.yaml b/src/image-default.yaml
index a725a9a5fb..82c53831f8 100644
--- a/src/image-default.yaml
+++ b/src/image-default.yaml
@@ -4,6 +4,8 @@ bootfs: "ext4"
 rootfs: "xfs"
 grub-script: "/usr/lib/coreos-assembler/grub.cfg"
 
+# Can also be oci-chunked
+ostree-format: oci
 # True if we should use `ostree container image deploy`
 deploy-via-container: false