nexus 4 - Ubuntu Touch Install Problem

I have installed the Ubuntu Touch Developer Preview on my Nexus 4.
It is the problem when I want to get back to my android 4.2.2 but I wipe all my data first, from factory reset, cache partition and also the dalvik cache.
Now, I cannot root my phone to android neither ubuntu because the pc cannot recognize my phone. Can you tell me what is my problem and how can I fix this? Thanks!