diff --git a/containers/jug/dev.Dockerfile b/containers/jug/dev.Dockerfile
index 4ac970530fd57e5be4e3703b8fe80d05e8f7de40..d9ff02a45583a639d500d08832017166a69dcccf 100644
--- a/containers/jug/dev.Dockerfile
+++ b/containers/jug/dev.Dockerfile
@@ -64,7 +64,7 @@ RUN declare -A target=(                                                 \
 ## Setup spack buildcache mirrors
 RUN --mount=type=cache,target=/var/cache/spack-mirror                   \
     spack mirror add spack-mirror /var/cache/spack-mirror               \
- && spack buildcache update-index -m spack-mirror                       \
+ && spack buildcache update-index spack-mirror                          \
  && spack mirror list
 
 ## Setup eic-spack buildcache mirrors