diff --git a/Transceiver52M/ms/bladerf_specific.h b/Transceiver52M/ms/bladerf_specific.h
index e9245d4d..798f3d78 100644
--- a/Transceiver52M/ms/bladerf_specific.h
+++ b/Transceiver52M/ms/bladerf_specific.h
@@ -255,7 +255,8 @@ struct blade_hw {
 		bladerf_log_set_verbosity(BLADERF_LOG_LEVEL_DEBUG);
 		bladerf_set_usb_reset_on_open(true);
 
-		setenv("BLADERF_DEFAULT_TUNING_MODE","fpga",1); // ensure blade 2 does not spend 10 seconds initializing host control
+		if (getenv("BLADERF_DEFAULT_TUNING_MODE") == NULL)
+			setenv("BLADERF_DEFAULT_TUNING_MODE","fpga",1); // ensure blade 2 does not spend 10 seconds initializing host control
 		blade_check(bladerf_open, &dev, "");
 		if (!dev) {
 			std::cerr << "open failed, device missing?" << std::endl;