Flashing other carriers' or International firmware, and LTE bands

I understand that it's possible to flash firmware from other carriers, or international firmware, on a T-Mobile G6 Edge, and that it will work, albeit with some glitches that can be patched. What isn't clear to me so far is whether flashing these firmwares has any effect, positive or negative, on the available LTE bands on the device. For example, would flashing AT&T firmware on this device enable bands 29 and 30 (which the actual AT&T variant supports), or is that a hardware limitation or some kind of deeper code that is not addressed by a typical firmware flash?

DISCLAIMER: I've searched. Lord, have I searched. All I could come up with was stuff relevant to earlier devices with different SoCs or whatever. If there's something obvious I've missed, please point me there, and feel free to laugh at me while doing so.

Why do carriers block features?

Sometimes the answer to this question is obvious. Verizon blocking google wallet was clearly so they could force people to use their own wallet app, whatever the hell it was. What I want to know is why on my AT&T Note 5 I don't have Auto Restart or Smart Manager. Both very useful features I would love to have, blocked by my carrier. How do either of these features effect AT&T? I'm sure there is plenty more blocked that I just don't know about.

Does anyone have any insight as to a logical reason a service provider would want to block stuff like this?

Here is a link to the video where I discovered these missing features:

https://www.youtube.com/watch?v=OPD8Aotsewg

Please excuse how boring the guy talking is.

Changing Carriers

Hi, I am new here and need some help with a Phone I just Bought.. I bought a Samsung Galaxy S3 ( SCH-S960L) Sprint ,,, Now when you turn on the phone it says Tracfone... But it is not a Tracfone But I believe it is a Straight Talk.
Anyway, I don't want to use Straight Talk Service, I want to unlock it so I can choose a different Carrier. I did Root this Phone.. Now How do I unlock it ? Any help would be real Cool . Thank you.

Is Indian Edge+ (SM-G928G) compatible with major Canadian carriers?

I would be moving to Vancouver in 2-3 months, so wanted to know if I can pop-in a GSM sim (of one of the good carriers over there) in the the unlocked version of Edge+ available in India (SM-G928G). Which all bands it supports, any idea?

Thanks

Stagefright patch from other carriers

Since basically every other carrier (AT&T, Verizon, Sprint) have already released Stagefright patches for the M8 and some even M9, rather than wait for T-Mobile's lame pathetic ass to get onboard with security, would it be possible to copy over the patched libraries from the other phones OTAs?

The AT&T update only weighs 28mb total, is it at all possible to extract the libs needed or are we waiting until next year (come on be realistic, you know it's not coming this year) when they decide to release Android M with Sense 7? I could care less about flashy features and other bs that is irrelevant, but for them to just overlook security updates is a real real b*tch move

What can we do, other than flash to cyanogenmod