This is found in Wiki in "Tips and Trick"; How to change to Region Free

Note my addition of the tip that you connect to the DVD port and NOT the normal serial port to the CO00.

Good luck,

Cheers,
Steve

#1: 8000s, 5500HC, 8000s, 861v8, 800Dv4, HD621
#2: 6000s, 6000C, 5000s, 6000s, 568.2mm, 598DP, 511
#3: 5500s, 5000C, 5000s, 561, 800v3, 518