I´ve tried the latest Android update into my Nexus 7 (1º gen) tablet.
Something went wrong in the middle of the process (it was something to do with the software, because the battery was full and the wifi wa working).
I had to restart the tablet, and after that I just couldn´t get to any app. Every single app or thing that I tried to use just would "unexpectedly" shut down. And after trying to shut down and on again the tablet, it was locked into the welcome screen (after the "Google" logo). The tablet wasn´t rooted in any way.
After a lot of reading and after searching on the net, I´ve found that the only way to use the tablet again was to do a factory reset.
I´ve done it. (One weird thing: it doesn´t appear the original "X" signal when initializing the thing, but the newest "bubble like" screen).
But even in that case, I still get freezed into the welcoming screen. And even if sometimes I get to enter the tablet, I can´t use the keyboard (trying to type any number will freeze the screen) and I cannot enter the settings screen.
Even if (after the factory reset) I can access the tablet, I can´t access the settings screen (so I can´t change any default, nor I can enter the "developers" tab in order to access the tablet in debug mode with my PC).
Is there anything I can do?
I´ve even tried completely discharging, without any luck (it does the same after charging it again).
Since then, I´ve tried the "factory reset" several times, and the problem remains.