Flashing AT&T 1520 (RM-940) to RM-938

[mewcatchew]

Can you flash the AT&T 1520 (RM-940) to RM-938? I'm sure it's been answered but I can't find a definitive answer. I know there was a was a work around for the AT&T Lumia 635 so I'm guessing theres a good chance for one for the 1520 as well.

I'm using a T-mobile SIM on my AT&T 1520 w/out any issues, all bands work (2g, 4g, LTE) and SMS/MMS are working fine. Really no need to flash it as the only thing I would gain is 1700/2100 3g band (although I am getting 3g on band 1900) but like most I prefer using an unbranded ROM. Thanks

 

[heywhitmarsh]

dial ##3282#
click accept
swipe up app bar and click settings
You can change network to manual and enable the 1700mhz band

 

[mewcatchew]

dial ##3282#
click accept
swipe up app bar and click settings
You can change network to manual and enable the 1700mhz band

Wow that was easy!

Now how about if I disable non-T-mobile bands... would that help anything or not needed? Thanks for the easy soulution!!!!!

 

[heywhitmarsh]

Wow that was easy!

Now how about if I disable non-T-mobile bands... would that help anything or not needed? Thanks for the easy soulution!!!!!

I've never tried to do that, but I haven't noticed any issues with connectivity leaving all bands active.

 

[mewcatchew]

I've never tried to do that, but I haven't noticed any issues with connectivity leaving all bands active.

Yeah I I'm just leaving all bands active. I can confirm band 4 AWS (1700/2100) is now working for me (confirmed through feild test). Reading up on it, AT&T has it disabled by default so people wont take their phones to T-mobile. Casual users would never find the setting to turn it on. I actually don't even need band 4 as I'm getting 3g on band 2 in my area, but instead of dropping to 2g in some places im getting 3g on the now active band 4, so I have improved connectivity. Again thanks for tip!

 

[jes1888]

I can do that on my Lumia 1520 does that means that we dont have to unlock our phones?

 

[mewcatchew]

I can do that on my Lumia 1520 does that means that we dont have to unlock our phones?

It doesn't unlock unlock your your 1520, just unblocks AWS band 4 (1900/2100) to use on T-mobile if your phone is unlocked.

 

[RumoredNow]

I can do that on my Lumia 1520 does that means that we dont have to unlock our phones?

If your phone was carrier branded, you need to unlock the SIM tray to use a SIM from another carrier.

Check your SIM lock status by opening dialer and typing ##7820#. The padlock icon will clearly show locked or unlocked and there is an entry field for an unlock number if you were provided one by the carrier or a 3rd party unlock service.

 

[mewcatchew]

If your phone was carrier branded, you need to unlock the SIM tray to use a SIM from another carrier.

Check your SIM lock status by opening dialer and typing ##7820#. The padlock icon will clearly show locked or unlocked and there is an entry field for an unlock number if you were provided one by the carrier or a 3rd party unlock service.

Not entirely true; if your phone has been unlocked and you've reset or flashed it it will still be unlocked but ##7820# will show a locked icon. ##7820# is really only good for entering unlock code when you don't have a different SIM card than the phone is locked to.

 

[RumoredNow]

Not entirely true; if your phone has been unlocked and you've reset or flashed it it will still be unlocked but ##7820# will show a locked icon. ##7820# is really only good for entering unlock code when you don't have a different SIM card than the phone is locked to.

True enough... In such cases you could submit a garbage string of any 20 numbers and it shows as unlocked. At least it did on a device I had with ATT branding after a reset.

 

[mewcatchew]

True enough... In such cases you could submit a garbage string of any 20 numbers and it shows as unlocked. At least it did on a device I had with ATT branding after a reset.

I Just tried, it didn't work. I wonder if you get it wrong enough times if it would lock up on you? My 1520 is ATT branded also (RM-940).

 

[RumoredNow]

Hmmm... I can't remember for sure which phone I did that on. I do remember looking at the screen after a reset and thinking what the heck a reset can't relock the SIM tray. I think I used the code from another phone I had in my email (distinctly different) and it took.

I guess I would not repeat it too often then. Still have the email with the code?


BTW I assume that the lock showing after a reset is purely cosmetic.

 

[mewcatchew]

I bought it unlocked, pretty sure it's refurb but it looked (looks) new. So I don't have the original unlock code. Yeah the lock icon is purely cosmetic as I'm using TMO SIM w/out any issues. At any rate I wont be throwing anymore codes in there just to be safe.

 

[jes1888]

i put the code mentioned above and the phone shows a open lock with the sim picture behind it and the text entry box i cannot enter anything. That means it is unlocked? I dont have another company simcard to confirm

 

[RumoredNow]

That means it is unlocked?

Correct, you are unlocked If the symbol looks like:

How to SIM unlock the Nokia Lumia 1520 from AT&T | Windows Central

 

[jes1888]

great!! It's unlocked then, thanks a lot for the info.

 

[RumoredNow]

That reminds me. I recently did a reset on my 1520.3 (Factory Unlocked) when it got a Firmware update via WDRT. A reset usually makes the SIM show as locked when dialing ##7820# and it did it again. I just looked.




So I entered in all zeros (0) until the check mark lit up. That shows you have the correct number of digits entered.




I tapped the check mark... It processed and then showed unlocked.




I then exited and dialed ##7820# again. Still shows unlocked.





This still shows as unlocked after a Soft Reset. YMMV.

 

[mewcatchew]

I shall test this.

Doesn't work. This is the 4th time its not taken I dont see a counter as how many failed attempts, but its four (ive kept track). Maybe my phone was unlock by a different method as I bought it unlocked on e, bay from a lot of 200 units.

 

[RumoredNow]

Mine was Factory Unlocked, sold with an unlocked SIM tray. Maybe that is the difference.

 

[mewcatchew]

So my 1520 was sold with an unlocked sim tray? I've seen vids of people using dongles and boxes plugged into pc's to unlock phones, is that what you mean?