When using the lumia software recovery tool, can i just download the required software at one point in time and install it on my phone later? Or do i have to install it at that moment itself? I use a lumia 520 and i'm rolling back from build 10149 to wp8.1 . The problem is that i don't have wifi at home and i'll use this phone itself as a wifi hotspot for my pc. Pls tell me if i need an internet connection for just downloading or for installing too.