diff --git a/src/eth/tb/taxi_xgmii_baser_enc_64/Makefile b/src/eth/tb/taxi_xgmii_baser_enc_64/Makefile
index 0999a9c..0061ff1 100644
--- a/src/eth/tb/taxi_xgmii_baser_enc_64/Makefile
+++ b/src/eth/tb/taxi_xgmii_baser_enc_64/Makefile
@@ -35,6 +35,7 @@ export PARAM_DATA_W := 64
 export PARAM_CTRL_W := $(shell expr $(PARAM_DATA_W) / 8 )
 export PARAM_HDR_W := 2
 export PARAM_GBX_IF_EN := 0
+export PARAM_GBX_CNT := 1
 
 ifeq ($(SIM), icarus)
 	PLUSARGS += -fst
diff --git a/src/eth/tb/taxi_xgmii_baser_enc_64/test_taxi_xgmii_baser_enc_64.py b/src/eth/tb/taxi_xgmii_baser_enc_64/test_taxi_xgmii_baser_enc_64.py
index 3791b3d..788e8ce 100644
--- a/src/eth/tb/taxi_xgmii_baser_enc_64/test_taxi_xgmii_baser_enc_64.py
+++ b/src/eth/tb/taxi_xgmii_baser_enc_64/test_taxi_xgmii_baser_enc_64.py
@@ -231,6 +231,7 @@ def test_taxi_xgmii_baser_enc_64(request):
     parameters['CTRL_W'] = parameters['DATA_W'] // 8
     parameters['HDR_W'] = 2
     parameters['GBX_IF_EN'] = 0
+    parameters['GBX_CNT'] = 1
 
     extra_env = {f'PARAM_{k}': str(v) for k, v in parameters.items()}