Well, it seems that when your motherboard is no longer the latest model around, Asus will stop updating the drivers and tools available for it, even though there are newer version out there which will work with your board. Express Gate is only of those tools. So, what exactly is Express Gate? It allows you to boot into a minimized Linux with basic function such as Skype, web browsing etc and all these straight from the BIOS. And in a way this is safer than you normal OS because the hacker will have compromise your Linux image in order to get something working, but the image is not saved and can be restored at every reboot. However, it is not said impossible because basically its a Splashtop OS which if the files are modified, it can still be hacked as described in this article:
Here is one of the description of Express Gate:
Technology developed by ASUS and introduced with their P5E3 motherboard that utilizes Splashtop, which is a Linux environment that is integrated onto the motherboard. With this technology users can turn on their computer and in five seconds be able to access the Internet using Firefox, online e-mail,Skype, and the Splashtop desktop without having to wait for their operating system to load.
Now, not all motherboard will support Express Gate. You will know when it says so. After the first Express Gate, there are many other version which differs in the way the image is installed. These are namely Express Gate SSD and Express Gate HDD. In any case, I notice that the latest version can be option via FTP from:
And the latest version for the first Express Gate is v18.104.22.168 as of today.