1) downloaded factory image 4.4.0
https://developers.google.com/... per il vostro device
2) extracted the tgz, then extracted the tar, then extracted the zip to get the system.img and boot.img files
3) moved these two files into my adb folder (for the fastboot/adb method)
4) downloaded SuperSU-v1.80.zip from
http://download.chainfire.eu/supersu
5) put SuperSU-v1.80.zip on my internal storage
6) downloaded the 4.4.1 OTA update zip from
http://android.clients.google.com/pa...M.7ed504f6.zip
7) renamed it to ota.zip (biggest filename in the world before!)
8) moved ota.zip onto my internal storage
9) rebooted phone into bootloader
10) opened command prompt from within your adb folder
11) connected USB cable
12) typed 'fastboot devices' to check the connection
13) typed 'fastboot flash system system.img'
14) typed 'fastboot flash boot boot.img'
15) used the volume and power buttons to boot into recovery (TWRP)
16) installed ota.zip
17) installed SuperSU-v1.80.zip
18) cleared dalvik and cache
19) rebooted phone