De-brand your AT&T Lumia 640 LTE.

[pankaj981]

No this removes the carrier approval check. It's set to 1 for all carrier ROMs. With it set to 0 it won't check the network to see if you're allowed. There is another value there Enabled which turns on/off the switch. Note this key is writable without Interop unlock. BTW this doesn't mean for certain you can tether as there are reports of browser string checks on some networks.

The ROM mentioned above is an unbranded country variant ROM and still it doesn't let you tether on Cricket Wireless unless you have it enabled in your plan. I guess with carrier profiles Microsoft has started performing validation checks with the carrier.

 

[ma678]

I believe wifi tethering is carrier depedant. If your plan has it enabled, your device will be able to handle it. I just tried it on my device and it was able to tether with my tablet.



I use the latest firmware with updated NVI from TMo on Koodo (a Telus sub) in Canada.
Posted from Windows 8.1

 

[jamssx]

As I said the ICS checks to see if it needs to authorize based on that registry key. When set to 1 it refers to a DLL that is mentioned in a different key as to how it should check. It also has the URL it should display when that check fails. The initial setting is set by provisioning. By setting it to 0 Windows will not check, however that does not mean it will work as because of various ways Android users have by-passed checks, the networks have other tests in place and can detect it (VPN is usually your best bet)

 

[cmfooballcoach]

Does anyone think that De-Branding and adding a TMO Rom will fix my data connection issues? I have a ATT 640 that I got unlocked. Started service with Walmart Family Mobile, and I have no data. Tried everything as far as APNs still no joy. According to the coverage map, I'm entirely in 4g LTE. Zero issues with text and voice. Works great. Want my data however.....Wondering if something in the ATT ROM is preventing data from working.

 

[pankaj981]

I'm not on WalMart family mobile plan but I've read posts where folks had to call them and have them add your IMEI to activate data. Not sure if that applies to you but it's worth a shot. Try calling them.

 

[jamssx]

I found in some but not all areas with the ATT ROM data wouldn't work on 2G. (Let alone LTE) It might also be that you're in a Band 12 LTE area, which means you have to enable 12 by reflashing and doing the NVI/factory reset. In any case Walmart is basically T-Mobile so you'll benefit from VoLTE and HD Voice etc.. All the things ATT disable..

 

[cmfooballcoach]

I've been on the phone with customer service like 4x. They have no clue. Of course they have no one with any knowledge available at the phone. They are reading crap from manuals. I'm truly at my wits end with this.

 

[pankaj981]

I've been on the phone with customer service like 4x. They have no clue. Of course they have no one with any knowledge available at the phone. They are reading crap from manuals. I'm truly at my wits end with this.

Have you tried inserting any other sim cards to verify it's not your sim?

 

[cmfooballcoach]

All 3 of the phones are acting the same way. So, I'm guessing that it's not my individual SIM.

 

[pankaj981]

Have you tried inserting your sim on a different device and see if you're getting LTE?

 

[theefman]

I ended up installing the 059X153 firmware.

WiFi tethering still doesn't work. The same message appears as before (contact AT&T).

Question for you, during setup were you able to setup the phone to US English? I used the Argentinian rom and during setup I don't have the option to select US English as my phone language so Cortana refuses to work unless its set to UK English which is the only other English option in setup. Thanks.

 

[Zura Pavliashvilil]

Hi. I want to know if band 3 or band 20 is accessible if I flash the device.. and what RM will I need for that..

 

[boonesmi]

Hi. I want to know if band 3 or band 20 is accessible if I flash the device.. and what RM will I need for that..

many people have tried different roms trying to get band 3, but ive not heard of anyone getting it to work. most likely its not even possible after all the rm-1073 (which is what the at&t phone is) is a different hardware revision then the versions of the 640 that have band 3. also checking the FCC database it shows all the bands tested and bands not tested but present on the rm-1073. band3 and band20 are not listed.

 

[Zura Pavliashvilil]

many people have tried different rom trying to get band 3, but ive not heard of anyone getting it to work. most likely its not even possible after all the rm-1073 (which is what the at&t phone is) is a different hardware revision then the versions of the 640 that have band 3. also checking the FCC database it shows all the bands tested and bands not tested but present on the rm-1073. band3 and band20 are not listed.

Thanks for your answer

 

[dlalonde]

mmm from what I understand from the OP on XDA Developers and he said he bricked it at first. Is this worth it?

 

[xandros9]

Just wanted to chime in and say that farther down, someone suggests the use of an Argentina ROM. I second this. It's not tied to any carrier although during setup it does not have a English (US) option. Just set it to Canada or something and fix the settings later in settings.

mmm from what I understand from the OP on XDA Developers and he said he bricked it at first. Is this worth it?

I think the risk here is just following the instructions. I think it'll be OK. I've done the same procedure myself with no issues, although it did take maybe 30 minutes of reading (spot skimming the thread, reading the other tutorial stuff it links to), not counting download prep.

 

[dlalonde]

Just wanted to chime in and say that farther down, someone suggests the use of an Argentina ROM. I second this. It's not tied to any carrier although during setup it does not have a English (US) option. Just set it to Canada or something and fix the settings later in settings.



I think the risk here is just following the instructions. I think it'll be OK. I've done the same procedure myself with no issues, although it did take maybe 30 minutes of reading (spot skimming the thread, reading the other tutorial stuff it links to), not counting download prep.

So long term you've had no trouble? I have an AT&T phone but there's no LTE option even though it's an LTE phone. So I'm tempted to try this with the T-Mobile version (which I had on my previous 640)

 

[xandros9]

So long term you've had no trouble? I have an AT&T phone but there's no LTE option even though it's an LTE phone. So I'm tempted to try this with the T-Mobile version (which I had on my previous 640)

I currently use my 640 as my daily driver, it was a $30 ATT deal.

It's SIM locked unfortunately.

I got LTE and VVM, I haven't noticed any issues other than what I presume is W10M issues. (I have some bugs like one app not notifying me of anything, Data Usage not being counted on cellular... but I think a hard reset should help.)

But yea, the Argentina variant (I think it was AR at least) matches the radio bands of our model. I have not noticed any significant issues. I got onto 10 without the Insider program too, although I did enroll in the Release Preview ring.

 

[dlalonde]

I currently use my 640 as my daily driver, it was a $30 ATT deal.

It's SIM locked unfortunately.

I got LTE and VVM, I haven't noticed any issues other than what I presume is W10M issues. (I have some bugs like one app not notifying me of anything, Data Usage not being counted on cellular... but I think a hard reset should help.)

But yea, the Argentina variant (I think it was AR at least) matches the radio bands of our model. I have not noticed any significant issues. I got onto 10 without the Insider program too, although I did enroll in the Release Preview ring.

And doing that, does that change the firmware?

 

[charktorious]

I've used this guide for three 640's now, and no bricks yet. I would just read the instructions carefully and take your time. Worst issue I had was prepping my PC to actually get the tools needed to do the firmware change. Also be aware that, AFAIK, this is a one way street as I'm not aware of any public CAB files to get you back to the AT&T firmware.

I went from the AT&T firmware to Tmo mainly because of BAND 12, which I can confirm works (via the Field Test app / turning off all options except BAND 12 as a test). Works a little better indoors now, which was the main goal.