diff --git a/org.jdrupes.vmoperator.runner.qemu/src/org/jdrupes/vmoperator/runner/qemu/Runner.java b/org.jdrupes.vmoperator.runner.qemu/src/org/jdrupes/vmoperator/runner/qemu/Runner.java
index e536479d3..fedaf1eaa 100644
--- a/org.jdrupes.vmoperator.runner.qemu/src/org/jdrupes/vmoperator/runner/qemu/Runner.java
+++ b/org.jdrupes.vmoperator.runner.qemu/src/org/jdrupes/vmoperator/runner/qemu/Runner.java
@@ -48,6 +48,8 @@
 import java.util.logging.Level;
 import java.util.logging.LogManager;
 import java.util.logging.Logger;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
 import org.apache.commons.cli.CommandLine;
 import org.apache.commons.cli.CommandLineParser;
 import org.apache.commons.cli.DefaultParser;
@@ -368,6 +370,11 @@ private void setFirmwarePaths() throws IOException {
                 break;
             }
         }
+        if (codePaths.iterator().hasNext() && config.firmwareRom == null) {
+            throw new IllegalArgumentException("No ROM found, candidates were: "
+                + StreamSupport.stream(codePaths.spliterator(), false)
+                    .map(JsonNode::asText).collect(Collectors.joining(", ")));
+        }
 
         // Get file for firmware vars, if necessary
         config.firmwareVars = config.dataDir.resolve(FW_VARS);