diff --git a/stack_orchestrator/data/container-build/cerc-mainnet-lotus/Dockerfile b/stack_orchestrator/data/container-build/cerc-mainnet-lotus/Dockerfile
index 3170fea6..9ecbd716 100644
--- a/stack_orchestrator/data/container-build/cerc-mainnet-lotus/Dockerfile
+++ b/stack_orchestrator/data/container-build/cerc-mainnet-lotus/Dockerfile
@@ -134,6 +134,7 @@ VOLUME /var/lib/lotus
 
 
 EXPOSE 1234
+EXPOSE 1235
 EXPOSE 2345
 EXPOSE 3456
 EXPOSE 1777
diff --git a/stack_orchestrator/data/container-build/cerc-mainnet-lotus/build.sh b/stack_orchestrator/data/container-build/cerc-mainnet-lotus/build.sh
index 70236044..25f58c98 100755
--- a/stack_orchestrator/data/container-build/cerc-mainnet-lotus/build.sh
+++ b/stack_orchestrator/data/container-build/cerc-mainnet-lotus/build.sh
@@ -3,8 +3,10 @@
 source ${CERC_CONTAINER_BASE_DIR}/build-base.sh
 SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 
+git stash
+
 # Use a release version tag to match the modified Dockerfile replaced in next step
-git -C ${CERC_REPO_BASE_DIR}/lotus checkout master
+git -C ${CERC_REPO_BASE_DIR}/lotus checkout v1.27.0-rc1-c
 
 # Replace repo's Dockerfile with modified one
 cp ${SCRIPT_DIR}/Dockerfile ${CERC_REPO_BASE_DIR}/lotus/Dockerfile