diff --git a/sys/dev/ixgbe/ixgbe_x550.c b/sys/dev/ixgbe/ixgbe_x550.c
index bcfbe14b30d..b5f1bc4f6ef 100644
--- a/sys/dev/ixgbe/ixgbe_x550.c
+++ b/sys/dev/ixgbe/ixgbe_x550.c
@@ -2802,9 +2802,9 @@ s32 ixgbe_setup_mac_link_sfp_x550a(struct ixgbe_hw *hw,
 				 (IXGBE_CS4227_EDC_MODE_SR << 1));
 
 		if (setup_linear)
-			reg_phy_ext = (IXGBE_CS4227_EDC_MODE_CX1 << 1) | 0x1;
+			reg_phy_ext |= (IXGBE_CS4227_EDC_MODE_CX1 << 1) | 0x1;
 		else
-			reg_phy_ext = (IXGBE_CS4227_EDC_MODE_SR << 1) | 0x1;
+			reg_phy_ext |= (IXGBE_CS4227_EDC_MODE_SR << 1) | 0x1;
 		ret_val = hw->phy.ops.write_reg(hw, reg_slice,
 					 IXGBE_MDIO_ZERO_DEV_TYPE, reg_phy_ext);