adb reboot recovery, fastboot and bootloader all result in either a reboot, or just a black screen. Seems somehow my recovery partition got hosed.Before you follow that thread, which is intense, try to reboot to recovery on your current OS. Use the adb reboot recovery command, and you should see the sideload through ADB option. I did. I then flashed 4.5.3, rebooted to setup (no wifi). Then, from adb in your laptop, adb install Kingroot and the JMZ Tools so that you can disable OTA. Disable OTA (pm block com.amazon.otaverifier), and let Kingroot install root with wifi enabled. Once root works, adb install Flashify to install the twrp image that you will copy to the device. Reboot to recovery, and flash supersu.zip.