[Lenovo Vibe X3 ROMs, Kernels, Recoveries, & Other ] arpit_nnd:
DISCLAIMER: I am not responsible for anything that happens while/after flashing these files. Your device's fate is your own responsibility. Proceed at your own risk.

WARNING: Your device's warranty WILL BE void after this.

This thread and all its contents are meant solely for the ROW variant: X3a40.

Starting from S217 you can unlock the bootloader directly using Fastboot commands without modifying any file.

I will assume that you are aware of the basics of fastboot, flashing, TWRP, etc.

Supported stock ROMs:

S217

UNLOCKING BOOTLOADER & ROOTING VIA TWRP

WARNING: Everything apart from data in external SD card will be wiped. Make sure to backup everything.

Make sure you read this post completely and carefully before implementing the steps.

Make sure you have backed up your data (everything apart from external SD card) on a PC or other storage.

Run this Fastboot command:

fastboot oem unlock-go

(Of course you need to put the phone in Fastboot mode to run a Fastboot command. Refer this if you don't know key combinations for X3a40)

Display turns off. That's all, you have unlocked the bootloader.

Hold power button for sometime to power off, release and hold again to power on.

No data gets wiped till this stage.

In theory(not tested all possibilities yet): Now if you make any modification to the filesystem or boot anything directly or after flashing via Fastboot, data gets wiped(first time only).

Confirmed behaviour:

If you boot TWRP directly (one-time TWRP) [fastboot boot twrp.img], it will boot, wipe and restart the device normally.

If you flash TWRP [fastboot flash recovery twrp.img] and reboot to recovery, TWRP will be overwritten by stock recovery, stock recovery will boot, wipe and restart the device normally.

Once restarted, you can setup the phone as there won't be any more wipes.

If you want to make any changes to the device's filesystem (e.g. get root access), you need to patch the boot image otherwise you will be stuck on Lenovo logo after making any changes and restarting.

The easiest way to do this is to flash the latest SuperSU zip which can always be grabbed from here: http://download.chainfire.eu/supersu-stable

To flash the zip you need TWRP. Either directly boot(one-time TWRP) or flash and reboot to TWRP (it won't be overwritten now).

On first TWRP boot you will be asked whether to allow modifications to system. Choose any option according to your needs and then install the SuperSU zip.

If you chose to allow modifications to system or made any changes manually, make sure you flash the SuperSU zip before restarting else device will get stuck on Lenovo logo.

If you somehow still somehow forget to implement the above step, and are stuck on Lenovo logo, don't worry. You can simply go to TWRP, flash SuperSU and reboot.

Once SuperSU is installed (more appropriately, boot image is patched by SuperSU zip), you can make any modifications you feel like. Good luck ! :highfive:

NOTE:

You don't need to unlock bootloader again if you have done it earlier. It stays unlocked until you manually lock it (via fastboot oem lock command). You can always check current status using this command: fastboot oem device-info

Data wipe will happen only if you unlock while on S217.

DOWNLOADS

ADB Kit + TWRP v2.8.7.7 by SevenMaxs (RECOMMENDED)

TWRP v3.0.2 by arpit_nnd (Material Theme) (EXPERIMENTAL; needs to let the the display timeout and awakened once to work)

Drivers + QFIL (UPDATED: 5/4/16)