Originally Posted by myepicyear
Okay, then yes - recovery, boot and system can all be safely fastboot erased. A custom recovery might do these things differently, so always verify what it will be wiping/formatting.
If you're in fastboot, the thing you never want to do is wipe/format the userdata partition. That's where everything important is. Everything else is basically replaceable.
Tell me if this steps are correct. I think that in a few days google will release android 4.4.3
1. Back to stock kernel (I can do this with Nexus Root Toolkit)
2. UnRoot the device (Always with NRT or via SuperSU)
3. Via Fastboot: Erase boot, Flash bot, Erase system, Flash system, Erase recovery, Flash recovery
5. Root again
Doing this steps i shouldn't lose anything, sure?