[Windows Phone 8 Development and Hacking] thals1992:
As there has been little progress made, I thought I could get the ball rolling myself. The purpose of this is to find a way to execute AT commands either on the device or via USB (for internet tethering purposes/general phone modification), and to discover how the bootloader works to devise a method to install a custom rom, or just installing unbranded/different roms for the same device, but different product code.

As a note before starting this, is my first device that's a Nokia, I'm taking this as a shot completely in the dark.

I haven't had any experience with Navifirm nor any of the Nokia utilities used in the past to flash either Symbian or WP7 devices, but I'm quickly learning.

PREREQUISITES:

http://www.seidea.com/2013/08/10/how-to-download-nokia-firmware-with-nokia-care-suite/ (the edited usergroupsconfiguration.cfg file)

http://www.seidea.com/2013/07/14/nokia-care-suite-pst-5-0-2013-27-1-3/ (the latest version of the Nokia Care Suite - 5.0 2013.27.1.3)

The USB drivers need to be installed first. The WinUSB drivers that were included are the only drivers that seem to apply to this device, but I went ahead and installed all the drivers in D:\Program Files (x86)\Nokia\Nokia Care Suite\Drivers

Driver Level Stuff

There are still a few devices shown without a driver. Here's the list

USB\VID_0421&PID_0660&REV_0100&MI_03 + USB\VID_0421&PID_0660&MI_03
USB\VID_0421&PID_0660&REV_0100&MI_06 + USB\VID_0421&PID_0660&MI_06
USB\VID_0421&PID_0660&REV_0100&MI_02 + USB\VID_0421&PID_0660&MI_02
USB\VID_0421&PID_0660&REV_0100&MI_01 + USB\VID_0421&PID_0660&MI_01
USB\VID_0421&PID_0660&REV_0100&MI_00 + USB\VID_0421&PID_0660&MI_00

I have no idea whats the purpose of these devices and using the driver update inside of Device Manager, it couldn't find anything.

Using my google-fu gave no results either.I could use some help in this department.

The following two are listed as Nokia USB Connectivity (which pst uses to run diagnostics)

USB\VID_0421&PID_0660&REV_0100&MI_04 + USB\VID_0421&PID_0660&MI_04
USB\VID_0421&PID_0660&REV_0100&MI_05 + USB\VID_0421&PID_0660&MI_05

which have the following files listed: winusb.sys WdfCoInstaller01009.dll and winusbcoinstaller2.dll

EDIT: found what the following devices functions are

The following is a walk-through for initiating these protocols

NOTE: The link above is not for the faint of heart. Its a link to a MSDN library. The walk-through assumes that you understand Windows already and have some background in programming.

The following process is the diagnostics TEST mode. It mostly relates to various hardware tests, like color pallets and tone generators.

So far, I have installed it on Win8Pro and started the Product Support Tool For Store. I then switched the product mode from Normal to Test and reboots into something that looks like a bootloader menu.

Since the text is blurry, It says:

NOKIA

ENOSW

RM680 1232.5957./9200.10211

181341 2013/02/28

RF INACTIVE​

When it has reconnected in the phone information tab, this is shown.

Software Version (Test)	RM860 1232.5957.9200.10211 181341 2013/02/28 //alpha_engine/ENO_LASER_F3
Software Version (Normal)	1532.5957.1318.3021
Product Code	059R224
Software Status	Up-to-date

NCSd Version (Normal)	1.24
Module Code	0205229
Basic Product Code	059N5M4
PSN Number	CGQ790279
Hardware Version	1000
Bluetooth Id	************
Public Id	****************************************
Wlan Mac Address	************ ************ ************ ************
Label App Version (Test)	Security LabelSW 4.24.0.55964

Hardware info
===========
MAIN ASIC
Main Asic Version	4.1

POWER ASIC
Pmic Model	1
Pmic Number	0
Pmic Revision	4

NFC
Firmware Version	1.26
Hardware Version	0.3
Model Id	0.1

DISPLAY
Manufacturer	0xFE
Display Type	0x90
Display Consecutive Number	0xBC
Display Horizontal Resolution In Pixels	768
Display Vertical Resolution In Pixels	1280

MAIN CAMERA
Model Id	18497
Revision	0.2
Serial Number	0A0101AE00000000
Manufacture Id	16
Sensor Id	10484100

FRONT CAMERA
Model Id	27184
Revision	3.0
Serial Number	0115323500000000
Manufacture Id	10
Sensor Id	0A6A3003

CAMERA FLASH
Hardware Design	18
Hardware Version	4
Flash Info 1	46
Flash Info 2	17

ACCELEROMETER
Manufacturer	KIONIX
Model	KXTNK-1000

ALS
Manufacturer	AVAGO
Model	QPDS-T900

PROXIMITY
Manufacturer	AVAGO
Model	QPDS-T900

Test Tab

When in this mode, the following options may be performed in NCS.

Self Test:

Test audio components, the accelerometer (gives positioning), gyroscope (same), the magnometer(gives positioning as well), the proximity sensor (pass/fail for if it works or not), nfc and its antenna, wlan, bt interface, temperatures (in Celsius) for Bluetooth, pa and osc (whatever those parts are), the display interface, the touch interface, camera interface and ois (idk what these are besides odd x,y values) and miscellaneous flash tests (which include a xenon charging time and its lifetime counter.

Touch Display Test:

Gives x and y coordinates for a single touch point.

Display Test:

Displays a white pattern, a black pattern, a checkerboard pattern, and different rgb shades with black.

Vibra Test:

Vibrates the phone based on percentage.

SIM Test:

Checks if a SIM card has been inserted. (fails with Verizon shipped sim EDIT: Now succeeds since PST update) It also is supposed to perform something else, but can't validate.

Mic Test:

Records and plays audio back through various inputs and outputs.

Accelerometer Test:

Gives "gravity" data in x,y,z format.

Audio Output Test:

Plays four tones through various outputs at three different volumes.

Another interesting thing: When powering off the phone and turning it back on, Windows attempts to find drivers for "Nokia BOOTMGR", but it occurs too quickly to install.

Can someone with experience with Nokia other phones contribute assistance? It seems like I'm just meddling with NCS and I could possibly brick my main phone. (I was told to only install the ffu it was designed for.)

Flashing ffus from the same device, but using a different product code

I haven't been around to know enough, and its unknown if the Lumia 928 will be launched on any different carrier or in a different country.

Anyways I'll quote snickler's post to summarize.

Photos/Screenshots will be posted later.

Thanks for reading the long post!