Quickboot from CM 12S ported to all CyanogenMod 12.x ROMs

QuickBoot is a Cyanogen OS feature developed by Qualcomm and Cyanogen for OnePlue One.
The objective is to reduce the boot-up time drastically by altering the shutdown / boot-up sequence.
This version of QuickBoot is taken from CyanogenMod 12S and modified by recognized developer arter97 to support Android 5.1 and fixed several NullPointerExceptions.

HOW IT WORKS:
Rather than turning down the device completely,
QuickBoot turns the device into Airplane mode, kills the applications, disables notification and button reactions, similar to how Windows 8 does.
The battery drain during QuickBoot is active is equal to the state of all applications killed & airplane mode.
Note that “reboot” actions remains normal, meaning the device will go into full shutdown / restart on reboot actions.

Flashing QuickBoot using custom Recovery:

Download the QuickBoot recovery flashable zip right here.

Flash the downloaded zip through custom recovery.

Enable QuickBoot from Developers options.
If Developer options is not enabled then enable developer options and then enable QuickBoot.

Follow the word of CAUTION: As the device is not completely off, devices with removable battery should use this with caution as pulling off the battery during QuickBoot active may potentially cause data loss.
For devices with removable battery, it is recommended to use “reboot” and wait for the screen to go off and then quickly replace the battery if needed.

Source