diff --git a/src/mainboard/google/zork/variants/morphius/overridetree.cb b/src/mainboard/google/zork/variants/morphius/overridetree.cb
index dbdf2e9a34..bee59e6a1f 100644
--- a/src/mainboard/google/zork/variants/morphius/overridetree.cb
+++ b/src/mainboard/google/zork/variants/morphius/overridetree.cb
@@ -43,7 +43,7 @@ chip soc/amd/picasso
 		.tx_pre_emp_amp_tune = 0x03,
 		.tx_pre_emp_pulse_tune = 0x0,
 		.tx_rise_tune = 0x1,
-		.tx_vref_tune = 0xf,
+		.tx_vref_tune = 0xd,
 		.tx_hsxv_tune = 0x3,
 		.tx_res_tune = 0x01,
 	}"