diff --git a/zephcore/adapters/gps/gps_module_cfg.cpp b/zephcore/adapters/gps/gps_module_cfg.cpp
index 260b1a4..07a6364 100644
--- a/zephcore/adapters/gps/gps_module_cfg.cpp
+++ b/zephcore/adapters/gps/gps_module_cfg.cpp
@@ -622,7 +622,7 @@ uint32_t gps_module_reapply_step(uint8_t step)
 		return 0;
 	}
 	gps_uart_send((const uint8_t *)list[step].sentence, strlen(list[step].sentence));
-	return (step + 1 < n) ? list[step].gap_ms : 0;
+	return ((size_t)step + 1 < n) ? list[step].gap_ms : 0;
 }
 #endif