[X Style (Pure) General] antariksh:
As the Nougat is rolling out for XT1572 devices, here's the guide for Flashing Stock Firmware using Fastboot for receiving Nougat OTA.

(Inspired by [MENTION=2001582]acejavelin[/MENTION] guide)

Prerequisites:

1) USB Drivers (Not needed for Windows 10)

2) Fastboot installed and working.

3) Stock Factory Images for Moto X Style (XT1572): https://firmware.center/firmware/Motorola/Moto X Style/Stock/XT1572/

Procedure:

1) Open a terminal or command prompt (Shift + Right click) window into the directory that contains the firmware files you extracted above.

2) Reboot the phone in Fastboot Mode (Reboot to Bootloader) and connect the USB Cable.

3) To verify if everything is perfect type in:

fastboot devices

If it shows your device serial number then you can be sure that it's properly connected.

4) Read the 'Notes' below.

6) Before proceeding, flash this commands to clean up the previous system's mess. This will get rid of the '(bootloader) Preflash validation failed' error when flashing gpt.bin (partition table).

fastboot erase cache
fastboot erase userdata
fastboot erase customize
fastboot erase clogo

5) Here's the actual commands to Flash the Stock Image. Please Enter them One-by-one, Don't create any .bat files or copy and paste the entire section.

[STRIKE]fastboot getvar max-sparse-size[/STRIKE]
fastboot oem fb_mode_set
fastboot flash partition gpt.bin
fastboot flash bootloader bootloader.img
fastboot flash logo logo.bin
fastboot flash boot boot.img
fastboot flash recovery recovery.img
fastboot flash system system.img_sparsechunk.0
fastboot flash system system.img_sparsechunk.1
fastboot flash system system.img_sparsechunk.2
fastboot flash system system.img_sparsechunk.3
fastboot flash system system.img_sparsechunk.4
fastboot flash system system.img_sparsechunk.5
fastboot flash system system.img_sparsechunk.6
fastboot flash system system.img_sparsechunk.7
fastboot flash system system.img_sparsechunk.8
fastboot flash modem NON-HLOS.bin
fastboot flash modem NON-HLOS.bin (Flash twice, if Prevalidation Error)
fastboot erase modemst1
fastboot erase modemst2
fastboot flash fsg fsg.mbn
fastboot flash bluetooth BTFM.bin
fastboot erase cache
fastboot erase userdata
fastboot erase customize
fastboot erase clogo
fastboot oem fb_mode_clear

Make sure you read whatever is happening on the prompt, do not miss any errors. (Scroll up the prompt and re-check everything before booting)

Notes:

1) This won't Lock your bootloader but you will be able to get OTA's.

2) For

receiving Nougat on RETASIA Dual Sim

, download: XT1572_CLARK_RETASIA_DS_6.0_MPHS24.49-18-8_cid7_subsidy-DEFAULT_CFC.xml.zip

There will be a 44mb update already queued when you boot the device. It will update the device to December 2016 Security Patch.

Reboot and you will be able to get Nougat OTA (911mb), if eligible.

3) If you didn't get the OTA Update, Flash this Nougat OTA

after

updating to December 2016 security patch: https://xdaforums.com/moto-x-style/general/ota-nph25-200-15-retasiads-t3636765 (Credits: [MENTION=6935483]Sagar_1401[/MENTION])

4) Different firmwares may contain a different number of system.img_sparsechunk.X files, you must flash the number you have in your firmware image in order. From what I have seen, most 5.1.1 firmwares have nine, 6.0 has eight, and 6.0.1 has eleven sparsechunks.

5) You must use a factory firmware image that is the same version as what you have installed or newer to successfully relock the bootloader, you cannot just grab the old (shipped) version from Moto's site. If you attempt to use a firmware image that is older than what you have installed currently, you will receive a Preflash Validation Error indicating such when you attempt to flash the partition table (gpt.bin).