The "increment MAC address by port number" hack applies only to EF1.

src/drivers/net/etherfabric.c

 	struct i2c_interface *i2c = &efab->ef1002_i2c.i2c;
 	struct i2c_device *i2cdev = &efab->ef1002_eeprom;
 
-	return ( i2c->read ( i2c, i2cdev, EF1_EEPROM_HWADDR_OFFSET,
-			     efab->mac_addr, sizeof ( efab->mac_addr ) ) == 0);
+	if ( i2c->read ( i2c, i2cdev, EF1_EEPROM_HWADDR_OFFSET,
+			 efab->mac_addr, sizeof ( efab->mac_addr ) ) != 0 )
+		return 0;
+
+	efab->mac_addr[ETH_ALEN-1] += efab->port;
+
+	return 1;
 }
 
 /** RX descriptor */
 	/* Read MAC address from EEPROM */
 	if ( ! efab->op->read_eeprom ( efab ) )
 		return 0;
-	efab->mac_addr[ETH_ALEN-1] += efab->port;
 
 	/* Initialise MAC and wait for link up */
 	if ( ! efab_init_mac ( efab ) )