A WIP kernel for the Lenovo K3 Note android phone is now available for download, courtesy of XDA developers. Developers says that it is not available for being use as daily driver as a lot of work still needs to be done. To install the Android 6 Marshmallow Kernel for Lenovo K3 Note, follow these instructions.
* Download the boot.img given from this link.
* Open any file manager.
* Go to /system/etc .
* Backup tfa98xx folder into extSDCard(External Memory).
* Delete the tfa98xx folder from /system/etc.
* Boot to Lenovo K3 note Custom Recovery(TWRP preferred).
* Flash the downloaded boot file to the boot section.
You can follow development of android marshmallow kernel for this Lenovo smartphone at this thread at xda-developers.