I made my R/W switcher zips this way. I flashed this kernel via Trwp. then once booted up i backed up kernel with Rashr apk...depending on your rom..im on cm12.1...i used cm12's switcher zips as base.....un-zip and deleted both boot img's from your switcher zips..then copy your new kernel img from the Rashr apk "Kernel-Backup's folder" into your un-zipped switcher zips...imporant...RENAME THE BACKED UP KERNEL to......"boot.img" (without quotes)..then re-zip both zips..re-sign the zips..Bam..R/W access with this kernel...