As Oilman stated when the firmware is updated using the official Liteon file for your serial number the MV protection is re-enabled. In fact, any hacks you have previously done such as region free, 3 hour mode or MV disablement are all undone. This is due to the fact that a new file is flashed into the eeprom that does not have these hacks present. What you need to do is to "hack" the new firmware either manually or using a utility such as ILOHacker and re-flash with the "hacked" new version. But as pointed out above, not all versions of the firmware have used the same hacking technique. So you may want to wait until someone else has done it before you try.
One final point. If your machine is giving you the performance you are satisfied with, don't always assume it is wise to upgrade the firmware. The Liteons have had inconsistency from build to build and some firmware upgrades have led to degraded perfomance on some machines. You should always ask yourself first if you have an issue that you believe the firmware may address. If not, why risk a bad hack or a bad upgrade?