Actually unlocking your lumia 710 either it's RM-809 or RM-803 for you to be able to use another network is as easy as making a sunny-side up egg for breakfast, well, yep kind of simple as that if you know how to cook? Kidding aside.
Ok enough of that trying to be funny stuff but really not working and let's go to the real deal.Follow this simple walk-through and you will be enjoying an unlock lumia 710 in no time.
First? Check your phone if you got an unlock bootloader or was it lock? This is critical coz this method of unlocking will not be possible and will not get any success result if your bootloader is lock.
But how to check? Click on my post in HERE on how to check if you got a lock or unlock bootloader, and IF your phone got a lock bootloader then YOU have to follow the procedure on the same post to get the bootloader unlock then come back here for the rest of the procedure, this time on sim unlocking.
So here we go, assuming that you already got a phone that was bootloader unlock.
Tool that you need:
NSSpro - By now I am hoping that you already know this program made possible by one of the important man in GSM world (bphreaks)
*Launch NSSpro (NssPro_0.54 - Latest)
*Under Simlocks click WP7 (see attached image)
*Put your phone into OSBL mode: Turn off the phone then press vol up (+) plug-in the USB but keep pressing the vol up button until the phone vibrates then release it.
Simply Click unlock and wait for the process to finish, it won't take long 2 minutes maximum.
*After the process is done disconnect your phone and put an unaccepted simcard if it ask for pin code just input 8 zeros.
*Congrats you now have a fully working sim unlock phone.
Figure 1.1
If you keep getting an error like this:
Looking for NAND disk...Done. Trying to p**** partition tables...Done. ---------------------------------------------------- FAT16 absolute address: 0x001F4200 FAT16 partition size: 0x0927C000 ---------------------------------------------------- Reading FAT16 raw...Error!
Just go to SETTINGS right next to WP7 and tick Lumia unlock - alternative search for old pc and try again.
Note: This method of unlocking works for PIN and PUK blocked phones.
If you got any further questions I would be happy to assist. The comment page is always open.