How can I find out which bands my phone supports Background:
I recently bought the Padfone X, and have been attempting to get it on my network. Part of this effort has been verifying information I have found online which claims that it supports LTE band 4.


  4G-LTE Bands: 1, 2, 3, 4, 5, 7 and 17


My network operator claims to support most phones that support AWS, specifically phones that operate on the 1700/2100 spectrum (which I believe corresponds to 4G-LTE band 4 / AWS 4 / etc.)

Problem:
Because I can't trust what I have read, I have been trying to answer this question: How can I find out what bands my phone supports just using Android / Apps?

What I have tried:
I have looked at this question asking about the current frequency band, which led me to try the two "secret codes" listed in the answers:


*#*#0011#*#*: Recognized as a code, but does nothing.
*#*#4636#*#*: This brings up phone information, but I don't see anything that looks frequency related. Screenshot here.


The device is rooted, so I can use adb shell to muck about if need be, but I don't know where to look.
Phones based on Qualcomm Snapdragon, like the padfone X, have their band settings stored in NVRAM, in a field called rf_bc_config. This will be set in the factory to match the band choices embedded into the hardware (radio components in the RF front-end on the device).

The value can be readout using Qualcomm service tools like QPST or QXDM, but it is not a human readable value, it is a bit-field and the bits are not in the order one might expect.

I do not know the mapping of the bitfield, but have seen people speculating on xda forum.

There are no apps to retrieve this information, because it is kept inside the modem software and never offered up to the application processor. The only information ever offered up to the android processor is the current connected band info.

It is possible to change these values in the NVRAM, and many people have, to try and force extra bands to work on their handset - of course, this is unlikely to result in useful performance on the new band, since the hardware support is not present.