diff --git a/lib/worker_multibuild.py b/lib/worker_multibuild.py
index ff05eaf..9f48875 100644
--- a/lib/worker_multibuild.py
+++ b/lib/worker_multibuild.py
@@ -75,8 +75,8 @@ def _get_dockerfile_contents(jobname, os_codename):
     """
     with open(join(path + jobname), "r") as file:
         contents = file.read()
-        # remove any line containing CMD or ENTRYFILE keywords
-        re.sub(r"(?m)^(CMD|ENTRYFILE).*$", "", contents)
+        # remove any line containing FROM or RUN keywords
+        re.match(r"(?m)^(FROM|RUN).*$", "", contents)
 
     return contents + {
         "focal": dockerfile_extra_contents_focal,