diff --git a/packer/ubuntuserver20.04.pkr.hcl b/packer/ubuntuserver20.04.pkr.hcl
index 97f9afe..7b3e767 100644
--- a/packer/ubuntuserver20.04.pkr.hcl
+++ b/packer/ubuntuserver20.04.pkr.hcl
@@ -160,7 +160,7 @@ build {
   post-processor "shell-local" {
     only   = ["vsphere-iso.ubuntuserver-baremetal"]
     inline = [
-      "qemu-img convert -f vmdk -o raw \\",
+      "qemu-img convert -f vmdk -O raw \\",
       "  /scratch/ubuntuserver-baremetal/${var.vm_guestos}-${var.vm_name}-baremetal-disk-0.vmdk \\",
       "  /scratch/ubuntuserver-baremetal/${var.vm_guestos}-${var.vm_name}.raw",
 "ls /scratch/ubuntuserver-baremetal -lash",