diff --git a/src/main.cpp b/src/main.cpp
index 95ac7c1c3a..25059f3c7f 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -718,6 +718,7 @@ void setup()
             setenv("TZ", "GMT0", 1);
         } else {
             setenv("TZ", (const char *)slipstreamTZString, 1);
+            strcpy(config.device.tzdef, (const char *)slipstreamTZString);
         }
     }
     tzset();