For LG BD390 the fix doesn't work once you have updated the firmware.

If you did the update, you can still go back to the firmware of Aug 2009


Once you have installed the past firmware, you can install the hack. Choose region 0 and save.

Then you can update again the firmware to the last release and the multiregion will still work.

Good luck

Here is a link to some of the earlier firmwares: Hope that helps