diff --git a/rancher-turtles-airgap-resources-chart/_service b/rancher-turtles-airgap-resources-chart/_service
index 6b8f891..415ab01 100644
--- a/rancher-turtles-airgap-resources-chart/_service
+++ b/rancher-turtles-airgap-resources-chart/_service
@@ -2,7 +2,7 @@
   <service mode="buildtime" name="kiwi_metainfo_helper"/>
   <service name="replace_using_env" mode="buildtime">
     <param name="file">Chart.yaml</param>
-    <param name="eval">IMG_PREFIX=$(rpm --macros=/root/.rpmmacros -E %img_prefix)</param>
+    <param name="eval">IMG_PREFIX=$(rpm --macros=/root/.rpmmacros -E %{?img_prefix})</param>
     <param name="var">IMG_PREFIX</param>
   </service>
 </services>
diff --git a/rancher-turtles-chart/_service b/rancher-turtles-chart/_service
index c3f6878..4f6fb26 100644
--- a/rancher-turtles-chart/_service
+++ b/rancher-turtles-chart/_service
@@ -2,14 +2,14 @@
   <service mode="buildtime" name="kiwi_metainfo_helper"/>
   <service name="replace_using_env" mode="buildtime">
     <param name="file">values.yaml</param>
-    <param name="eval">IMG_PREFIX=$(rpm --macros=/root/.rpmmacros -E %img_prefix)</param>
+    <param name="eval">IMG_PREFIX=$(rpm --macros=/root/.rpmmacros -E %{?img_prefix})</param>
     <param name="var">IMG_PREFIX</param>
     <param name="eval">IMG_REPO=$(rpm --macros=/root/.rpmmacros -E %img_repo)</param>
     <param name="var">IMG_REPO</param>
   </service>
   <service name="replace_using_env" mode="buildtime">
     <param name="file">Chart.yaml</param>
-    <param name="eval">IMG_PREFIX=$(rpm --macros=/root/.rpmmacros -E %img_prefix)</param>
+    <param name="eval">IMG_PREFIX=$(rpm --macros=/root/.rpmmacros -E %{?img_prefix})</param>
     <param name="var">IMG_PREFIX</param>
   </service>
 </services>