I have a P8Z77-V LX board and Win 8 pro x64 and had the same sort of trouble, just a few hours ago, but have got version 1902 up and running now. I did it like this
Go to Asus site - http://www.asus.com/Motherboards/P8Z77V_LX/ - if you have the LX board
Click on "support"; then "download";then Click on "Bios"
select and download the file "P8Z77-V-LX-ASUS-1902"
note where it is saved, go there and Unzip it
Open AI Suite II (2.01.02), select "update", and choose "Update bios from file"
Click "next", and select the unzipped (.cap) file "P8Z77-V-LX-ASUS-1902"
When the file has loaded, a"next" button will appear - click on it
I cannot quite remember whether there are more screens, but you are led to a progress bar, after which you are invited to reboot
just for the record, my problems were that I used the ASUS homepage automatic detection and it had me down as a "P8Z77-V S" mainboard, and led me to the wrong BIOS. I kept getting a message to the effect I had the wrong BIOS module, which was right. I think my antivirus was preventing the auto detection running correctly