1. Plug the SIM card you are going to use with the gps into a phone.
2. Turn off the sim lock. This is very important
3. Cancel any call diverts. this is very important
4. Fully charge the battery for at least eight hours
5. Insert the sim into the gps.
6. Go outside, into an area with a clear line to the sky from all angles, a field, or park is great.
7. Turn on the unit,
8. Wait. At least three minutes.
9. Cal the SIM card in the gps.
10. If all is good, the phone will show two rings and hang up.
11. Within 10-30 seconds, you will receive an SMS message with the gps co ods and a link to google maps,
I spent ages mucking around to get this working and until I did the above, it did not work!
Follow the above, to the letter and it's 100% perfect.