@vignesh said:

I build al the img files required . flashed system.img, boot.img and recovery.img (build twrp recovery) over fastboot. now the mobile stuck at ASUS logo while turn it on.. please help

You must not use inline kernel building because this way you will get a broken kernel.
You should figure out which ramdisk is needed for Ubuntu Touch. And make changes in stock ramdisk for this.