I used the hack posted for the HT-C5550 by paradimn on June 25, 2010. This works for the HT-F5550HK as well. The hack is:

To change the DVD from region 5 (Asia) to region 9 (region free) follow these steps using the remote control.

1. Ensure that there is no disk in the tray.

2. Switch the player off and then back on. This is necessary to clean-boot the firmware.

3. Wait until the main menu page appears and the player stops doing anything.

4. Press the eject button to open the tray. (The button is between the "Power" and "TV Power" buttons at the top of the controller.)

5. Press the eject button to close the tray.

6. Wait while the player searches for a disk.

7. As soon as the "No Disk" message appears at the top left corner do the following.

8. Press the REPEAT button just above the TV channel selector at the bottom right of the controller.

9. Enter 5 3 8 1 4 on the number pad.

10. The region code "5" should appear at the top left corner of the screen.

11. Enter a "9" to make the player region free. (Enter a region code if you want to lock the player to another region for some obscure or perverse reason.)

12. Power down and power up again.

13. Play a foreign DVD to verify the change.

Now the tricky bits. This process is timing dependent.

Firstly, you must start entering the code just after the "No Disk" message is shown and before the message disappears. If you jump the gun or miss the boat (isn't English great!) it won't work.

Secondly, the REPEAT key is part of the code. All six keys must be entered smoothly as "REPEAT 7 6 8 8 4". The entry gets timed out so you can't stop in the middle and restart. Don't bash away like crazy, just do it smoothly and briskly.

I can't guarantee that this player does not have a region change counter so I would be a bit careful about changing regions back and forth. I also can't guarantee that this will work with all released firmware. Samsung seems to take this crazy region bastardry very seriously for some reason.

For people from other parts of the world, all region codes are as follows

1 2 9 3 3 4
2 5 7 5 3 8
3 5 6 7 3 2
4 7 6 8 8 4
5 5 3 8 1 4
6 2 4 4 6 2