diff --git a/dockerfiles/Synapse.Dockerfile b/dockerfiles/Synapse.Dockerfile
index fe86cc5d..debea1e7 100644
--- a/dockerfiles/Synapse.Dockerfile
+++ b/dockerfiles/Synapse.Dockerfile
@@ -24,7 +24,7 @@ COPY keys/* /ca/
 RUN openssl genrsa -out /conf/server.tls.key 2048
 
 # generate a signing key
-RUN generate_signing_key -o /conf/server.signing.key
+RUN /synapse/.venv/bin/generate_signing_key -o /conf/server.signing.key
 
 WORKDIR /data
 
diff --git a/dockerfiles/synapse/start.sh b/dockerfiles/synapse/start.sh
index eca41cd2..ef89b1e5 100755
--- a/dockerfiles/synapse/start.sh
+++ b/dockerfiles/synapse/start.sh
@@ -24,5 +24,4 @@ openssl x509 -req -in /conf/server.tls.csr \
   -CA /ca/ca.crt -CAkey /ca/ca.key -set_serial 1 \
   -out /conf/server.tls.crt
 
-exec python -m synapse.app.homeserver -c /conf/homeserver.yaml "$@"
-
+exec /synapse/.venv/bin/python -m synapse.app.homeserver -c /conf/homeserver.yaml "$@"