Stuck at Team Win Recovery Project at Boot when updating LG G-pad 7.0

Hi, I have an LG G-pad 7.0 v410 that has been rooted with purple drake and I have installed TWRP and Flashify. I stupidly accepted a system update because the tablet is AT&T and I though it was an AT&T update. Anyway, now I am stuck at boot with the Team Win recovery project.. I tried the option Reboot->System but it comes back to the same screen. I see at the mount option that there is an X next to Data, Cache, sdcard boxes but not next to the "System", though I don't know if that is related.

I am really a newbie (obviously!), so if there is any "cure" please explain the steps in detail.

Thanks in advance.