Enabling LTE Bands from the LG Secret Menu?

[Dishe]

I have a PM edition that has been cross flashed to a ULM. Someone pointed out that the ULM version doesn't officially have certain US bands like 12, which are very important for T-mobile/AT&T here. But the original PM version does have those.
I went into the service menu (*#546368#*710#) and found the bands listed under the field test mode and went and disabled everything other than B12. At first there was no service, but after a quick toggle of airplane mode, I'm connected to Band 12 (according to signal spy at least). I even did a speed test to make sure it was sending / receiving data. I was previously connected to Band 2 before doing this.

I'm not sure what this proves- is B12 only available because my hardware is the PM version? Or are the bands controlled by software? I have to admit, the service menu seems to offer all the possible bands this SoC is capable of, including B71 . That's interesting because I thought B71 is only on the T-mobile version and not available on the ULM or PM versions. Does fiddling with the service menu essentially let you enable whatever band you want on any edition of this handset?

 

[mr3p]

I have a real ULM and connect to LTE 12 without issue. IIRC, your PM crossflashed to ULM will work on all T-Mobile LTE bands except 71. If you feel like experimenting, there were rumors that AWM firmware may enable band 71 although I don't know recall anyone specifically testing it.

 

[Dishe]

I have a real ULM and connect to LTE 12 without issue. IIRC, your PM crossflashed to ULM will work on all T-Mobile LTE bands except 71. If you feel like experimenting, there were rumors that AWM firmware may enable band 71 although I don't know recall anyone specifically testing it.

I'm thoroughly confused now, I swapped to another "ULM" (also crossflashed from Sprint- the first had a physical defect that I returned and swapped for another), and didn't do anything to the service menu and STILL connected to the same bands according to software reporting. Bands that according to online resources, the ULM isn't supposed to support. Yet it does, and you say your real ULM does too. So obviously the spec sheets online are wrong and I have no idea what bands any of these handsets actually support or if doing anything in the service menu makes any difference at all.
Someone said another edition of this handset (european maybe?) had his menu showing a different set of bands available to select than mine, so I wonder if this is controlled via the firmware or the hardware (NVRAM values or whatever?). The service menu appears to just serve as a way to isolate bands available to test if certain ones work where you are. And on my PM turned ULM, band 71 is listed. I don't have 71 around me so I have no idea if this is real or not.
Wish there was more (accurate) information about there about how this works.

 

[mr3p]

I'm on T-Mobile and usually connect to LTE 2, 12 or 66. Of those I'd say most of time 66. I've never seen a connection to 71, which I always figured meant that its not supported by the phone. If you are interested in trying to get 71, flash AWM and see what happens.

 

[Dishe]

So it follows the firmware or it follows the hardware (nvram values)?

 

[loonycgb2]

ALL g7's other than the g7+ are capable of the same bands. They are software enabled or disabled or even hidden.

If you can access ##data# from dialer and input the msl code to get to band priority then you can connect whichever you want.

If not the secret menu is needed to access the ones you need.

If the firmware did not include the band in secret menu then it has been disabled. At that point you need to access via a nvdata application like cdma workshop to enable them forcefully, but it will clear out after each restart since cdma workshops adds the band temporarily.