diff --git a/config/hwlab-hwpod-preinstalls/constart-71freq-c.yaml b/config/hwlab-hwpod-preinstalls/constart-71freq-c.yaml
index 10c32872..703779ec 100644
--- a/config/hwlab-hwpod-preinstalls/constart-71freq-c.yaml
+++ b/config/hwlab-hwpod-preinstalls/constart-71freq-c.yaml
@@ -43,6 +43,7 @@ hwpodPreinstall:
     scope: external
     port: COM4
     baudRate: 921600
+    backend: pyserial
     encoding: utf8
   boardComm:
     endpoints:
@@ -64,6 +65,7 @@ hwpodPreinstall:
       id: uart/1
       port: COM4
       baudrate: 921600
+      backend: pyserial
     probes:
       - id: main41.ai0.current
         endpointRef: main41
@@ -129,6 +131,7 @@ hwpodPreinstall:
           id: uart/1
           port: COM4
           baudrate: 921600
+          backend: pyserial
         probes:
           main41.ai0.current:
             endpointRef: main41