Which 640?

[tpapictures]

If I wanted a 640 for T-Mobile in the states, would I be able to use either the LTE or the Double-Sim? Or is their only one in particular that would work? Does anyone know?

 

[libra89]

You'll have to get the correct model number to be able to get LTE. If you have access to an AT&T one, you would get LTE for sure but you have to unlock it first through AT&T's website.

B&H Photo sells 640s that will work with T-Mobile's network and get you LTE as well.

 

[tpapictures]

You'll have to get the correct model number to be able to get LTE

Ok, I thought there were only two models, the LTE or the double SIM. I didn't think they varied more than that. So an unlocked AT&T for sure and other than that, as long as I'm happy with just regular 4G, any unlocked version whether it's the single or double SIM will work?

 

[libra89]

Ok, I thought there were only two models, the LTE or the double SIM. I didn't think they varied more than that. So an unlocked AT&T for sure and other than that, as long as I'm happy with just regular 4G, any unlocked version whether it's the single or double SIM will work?

You almost got it, but not quite. The bands in the phone are very important!

For example, the ones that B&H Photo sell are capable of LTE, and are double SIM. Smartphones Unlocked Cell Phones & Mobile Phones | B&H
Those are RM-1075. RM-1077 will get you HSPA+ speeds, same for RM-1072. By the way, the AT&T (and the rare T-Mobile one too) one is RM-1073, which is also guaranteed LTE.

T-Mobile uses the bands 2,4, and 12 for LTE, or the frequencies: 1900, 1700/2100 (AWS), and 700. It has to have at least the 1900 frequency to work, but I don't recommend only that one though, or else your speeds will suck.

 

[pankaj981]

You could always buy the AT&T version for 30 bucks, unlock it for free and start using it on T-Mobile. To enable WiFi calling you'll need to flash to the T-Mobile ROM. The T-Mobile 640 is hard to find these days.

 

[tpapictures]

You almost got it, but not quite...

Wow, thanks for all the great info! I did know that the bands are important but I thought there were literally only TWO versions of this phone. As in, two model numbers. Is there a site that lists these and what their different bands and features are? Also, in the end, if you don't live in an LTE-heavy area, you'll not likely to get much more than HSPA+ anyway right?
With respect to the bandwidths, how many do you have to be able to receive to get the full strength of signal that the phone is capable of? I seem to recall that in the days when 3G was the fastest, you had to be able to get three bands minimum.

You could always buy the AT&T version for 30 bucks, unlock it for free and start using it on T-Mobile. To enable WiFi calling you'll need to flash to the T-Mobile ROM. The T-Mobile 640 is hard to find these days.

I don't think I've ever used or had any need for WiFi calling. But in any event, that AT&T version for $30, is that the pay-as-you-go one I see online? Is there a model number I need to look out for for that? And AT&T just gives away the unlock code for free? Why would they do that?

Another question for both of you. I actually live in France and am looking into this for my dad who's on T-Mo but if the price is that good, I'd love to know if I can get it to unlock it and use it on my carrier here, Bouygues. How would I check that?

 

[tpapictures]

Just looked into it, apparently my mobile provider in France uses 800, 1800, and 2600 for LTE. So I guess I'd be fine? Does that mean I'd also be ok in places where I drop to 3G or even 2G or do I need to check those bands as well?
Thanks!

 

[tpapictures]

You could always buy the AT&T version for 30 bucks, unlock it for free and start using it on T-Mobile.

So this Lumia 640 LTE can go to a FULL Windows 10? Even though it's a pay as you go phone? I just read this in another thread, is it true?
"The only firmware update for W10M for older phones was to make sure they were on official Denim. That's the only pre-requisite for W10M. The Lumia 640 will not get a separate firmware update for it, and the update will be exactly like using the Windows Insider to get to .164."
That seems to suggest a proper Win10 like the 950, 650 won't get released for 640. But then there was that list of all the phones getting it and the 640 WAS on there, so what is this person talking about?

I'm wondering, if unlocking it works fine and I get my SIM card in there and I'm running the phone fine, could I possibly download an 8.1 ROM from MS of the Lumia 640 LTE that my French carrier released? Because I think they're already getting the Win10 OTA.

 

[pankaj981]

I don't think I've ever used or had any need for WiFi calling. But in any event, that AT&T version for $30, is that the pay-as-you-go one I see online? Is there a model number I need to look out for for that? And AT&T just gives away the unlock code for free? Why would they do that?

The 30 bucks version is the prepaid phone. You can request an unlock from the guide here. *****Read point 1)*****

So this Lumia 640 LTE can go to a FULL Windows 10? Even though it's a pay as you go phone? I just read this in another thread, is it true?
"The only firmware update for W10M for older phones was to make sure they were on official Denim. That's the only pre-requisite for W10M. The Lumia 640 will not get a separate firmware update for it, and the update will be exactly like using the Windows Insider to get to .164."
That seems to suggest a proper Win10 like the 950, 650 won't get released for 640. But then there was that list of all the phones getting it and the 640 WAS on there, so what is this person talking about?

I'm wondering, if unlocking it works fine and I get my SIM card in there and I'm running the phone fine, could I possibly download an 8.1 ROM from MS of the Lumia 640 LTE that my French carrier released? Because I think they're already getting the Win10 OTA.

The phone will get a firmware depending on where you live. For example, I was running an Argentina CV ROM and it did receive a firmware update before WM10. As I typing this my phone is installing the official WM10 on the Mexico ROM. I reverted back to 8.1 from official WM10 on the Argentina ROM >> Changed ROMs from Argentina to Mexico >> and installing the official WM10 update. You may as well flash to the French ROM and get the official update but I would strongly suggest sticking to the Mexico CV unbranded ROM since this is the closest unbranded ROM for the RM-1073 AT&T variant. For the unbranding tutorial refer to this link.

 

[tpapictures]

You may as well flash to the French ROM and get the official update but I would strongly suggest sticking to the Mexico CV unbranded ROM since this is the closest unbranded ROM for the RM-1073 AT&T variant.

Thanks for the help...
So I could get a completely unbranded 640 LTE ROM with no splash screen, just straight Microsoft, I imagine. Is there a list somewhere of all the available ROMs? Is that something MS provides for people using the Device Recovery tool for example?

Now, I'm reading more and more here and elsewhere and what I'm getting is that Win10's not even fully released all over the place yet for the 640 and even some other phones. In some cases for the 640, carriers will release a FW update and in others they won't. But the OS will go out as soon as those carriers have reviewed it for functionality. (Am I right?)

This is where I get a bit confused... I imagine to be able to OTA a full Win10 ROM to you, MS would have to have made an unbranded unlocked Lumia 640 LTE with RM-1073. Like the unbranded 650 they're selling now or the 640 LTE you can buy on their site, I imagine. So, did they make one or not? Because if they never did, then there isn't going to be an unbranded full Win10 ROM for the 640 LTE.

The bands seem to check out fine for my dad on T-Mo in the States, (if not I flash him a T-Mo ROM for RM-1073) but I still don't know if my carrier Bouygues Telecom in France has the same 4G, 3G and LTE bands (they're releasing LTE this year). I just want to understand...
1. How do I determine which bands MY carrier sends out? And then how many does the phone need to have for full compatibility?
2. What is CV ROM?
3. Why does Mexico have this unbranded ROM?
4. I pick up the ATT Go, unlock it via email, leave it as it is and upgrade advisor will tell me MS is working with my carrier (AT&T) to bring Win10 soon.
Correct or no?
5. I pick up the ATT Go, unlock it via email, flash my French firmware and upgrade advisor will tell me in French that MS is working with my carrier (Bouygues) to bring Win10 soon.
Correct or no?
6. I pick up the ATT Go, unlock it via email, flash the Mexico firmware and upgrade advisor will tell me Win10 is ready and I can enjoy it now. And that is a FULL Win10 (I say "full" as opposed to Insider Preview).
Correct or no?

Sorry for the repetition, I wanted to make this clear as day for myself.
Thanks so much for trying to help me understand all this. Really appreciate it.

 

[pankaj981]

Is there a list somewhere of all the available ROMs? Is that something MS provides for people using the Device Recovery tool for example?

Yes its an unbranded ROM with no carrier bloatware. Updates will be pushed directly by Microsoft. There isn't a list per se but all Country Variant (CY) ROMs are unbranded.

Now, I'm reading more and more here and elsewhere and what I'm getting is that Win10's not even fully released all over the place yet for the 640 and even some other phones. In some cases for the 640, carriers will release a FW update and in others they won't. But the OS will go out as soon as those carriers have reviewed it for functionality. (Am I right?)

Certain carriers might push a firmware prior to the update but that doesn't mean officially upgraded devices won't get the firmware when released by Microsoft.

This is where I get a bit confused... I imagine to be able to OTA a full Win10 ROM to you, MS would have to have made an unbranded unlocked Lumia 640 LTE with RM-1073. Like the unbranded 650 they're selling now or the 640 LTE you can buy on their site, I imagine. So, did they make one or not? Because if they never did, then there isn't going to be an unbranded full Win10 ROM for the 640 LTE.

Microsoft does sell unlocked unbranded 640s (also known as Country Variants), not in the US. Since the RM-1073 is more suited for the Americas region one could flash any CV ROM from Latin America or North America

1. How do I determine which bands MY carrier sends out? And then how many does the phone need to have for full compatibility?

Your carrier
RM-1073 supported bands

2. What is CV ROM?
3. Why does Mexico have this unbranded ROM?

CV = Country Variant, all CV ROMs are unbranded

4. I pick up the ATT Go, unlock it via email, leave it as it is and upgrade advisor will tell me MS is working with my carrier (AT&T) to bring Win10 soon.

Yes

5. I pick up the ATT Go, unlock it via email, flash my French firmware and upgrade advisor will tell me in French that MS is working with my carrier (Bouygues) to bring Win10 soon.

If you are flashing the unbranded French CV ROM then you should get the update right away. If you flash your carrier ROM then you might have to wait depending on when your carrier approves the update

6. I pick up the ATT Go, unlock it via email, flash the Mexico firmware and upgrade advisor will tell me Win10 is ready and I can enjoy it now. And that is a FULL Win10 (I say "full" as opposed to Insider Preview).
Correct or no?

Yes you will get the official WM10 update after installing the Upgrade Advisor app.

 

[tpapictures]

Thank you so much.
So I guess I was wrong about Bouygues. Clearly according to that amazing site you sent me to, I'm only going to get one of 3 4G bands. Not good enough. Shame. Great price, great phone.

If you are flashing the unbranded French CV ROM then you should get the update right away. If you flash your carrier ROM then you might have to wait depending on when your carrier approves the update

However, as you had mentioned before earlier, the French CV ROM isn't necessarily for the RM-1073, right? In fact a check on the lumiafirmware site shows that the French CV is for the 1072. So there could be problems in the operations of the phone, errors, etc.

 

[pankaj981]

From my experience you can still flash the RM-1072 ROM and it will still work, network bands will be retained (new bands won't be unlocked since it's hardware dependent). Despite of it being possible I would still stick with the Mexico ROM since it's unbranded and the only with been the French ROM would be the default setup screen...one would be French other in Spanish.

 

[tpapictures]

From my experience you can still flash the RM-1072 ROM and it will still work, network bands will be retained (new bands won't be unlocked since it's hardware dependent). Despite of it being possible I would still stick with the Mexico ROM since it's unbranded and the only with been the French ROM would be the default setup screen...one would be French other in Spanish.

But regardless of Spanish or French, (I speak both, so not a problem anyway) even the Mexican ROM is an RM-1073 and when my Network SIM goes in the phone, if I've learned everything correctly from you, I'll be stuck with only the 2600 band when I also need 800 and 1800 for 4G on my network. :unhappy:

 

[pankaj981]

That's correct. Your best bet would be to get the non-Americas variant.

 

[tpapictures]

That's correct. Your best bet would be to get the non-Americas variant.

A guy over on XDA says that because the 1073 and 1072 have the same SoC (MSM8926 + WTR1625L), those European bands will become available with a European 1072 ROM on the phone. You ever heard of that? I didn't think radio had anything to do with SoC but my knowledge there is limited.

 

[pankaj981]

Nope that won't work.

 

[tpapictures]

Nope that won't work.

Didn't think so. Cool, thanks. Is there any way I can simulate what only running 4G on one band would feel like on my current phone for example? Is it just going to be an overall sluggishness with anything web related? Or will it be maybe only felt in heavier data download? It would be only Band 7 that I'd get.

 

[pankaj981]

4G is fast, depending on your carrier's data speeds. For example my carrier, cricket wireless caps my LTE at 8mbps so that's the best I get. My previous carrier T-Mobile gave 40mbps LTE while HSPA+ at 15-16mbps.

 

[tpapictures]

4G is fast, depending on your carrier's data speeds.

I just want to try to understand how much slower will my data be with only band 7 running. I thought you needed all your carriers bands running to get proper speeds. So as a comparison point, I'm getting about 26.5 Mbps down and 6 up on average on my carrier with my current Lumia 925 which has all three of my carrier's bands available for use.

I'm heavily confused about something that probably has to just do with crappy reporting online: Are all 4G bands the same as LTE bands? Because I see them referred to, for example, as 1800 and then in another place as "Band 3". I understand that there is also an 1800GSM but that's 3G, right? Different band altogether?