Re: How do I unlock an AT&T Lumia 640 Windows phone?
I've unlocked 4 AT&T GoPhones (2 for me 2 for a friend) 4 different times and it's always gone smoothly. I'm actually doing one right now at the moment.
I use the Firefox browser and have not had any issue with requesting the code.
The way I do it is as soon as I get one home before I even remove the phone from the packaging I go to the AT&T unlock page:
https://forums.windowscentral.com/e...tt.com%2Fdeviceunlock%2F%23%2F&token=udGl1DCU
Check the "I have read..." thing on the bottom and hit continue.
Then on the next page select NO to "are you an AT&T wireless customer" and then enter the captcha characters.
On the next page enter the IMEI number right off the unopened packaging of the GoPhone. Enter name and email and submit.
Go to your email immediately and respond to the email they send to you by clicking the link inside. You'll get the code in 2-3 days.
Meanwhile, after responding to the email, I open the packaging and remove the phone.
At this point DO NOT turn the phone on or put the battery in (yet).
First, I remove the cover from the back of the phone and remove the AT&T sim card that is in it. I just toss it. Then I put the battery in and replace the cover. Then I turn the phone on and I get to work on setting the phone up adding my Microsoft email and downloading/updating apps etc using WiFi, arranging the start page, tweaking settings etc while I wait for the code.
By the time the code arrives, my phone is totally set up.
When you get the code, you can either put your non AT&T sim in (in my case T-Mobile) and this will bring up the unlock code screen and then you can enter the code.
Or you can enter ##7820# on the dial pad from the Phone tile and this will bring the unlock code screen up. They give you 10 tries to get it right.
It has always worked for me the first try.
As I said, I use the phones with T-mobile pay as you go $3 a month plan.
All phones work great. I actually disable the LTE completely (via ##3282#) since 4G seems to work very well and battery life seems better.
IMO, the 640 is a MUCH better phone than the 635. It is also better than the androids in the $150 or less range that I tried.