We are aware of the problem, it will be solved as soon as possible.
Hey, I'm trying to download the bt4-r2.iso, but it is "NOT FOUND" ...404 error.
What's up? Where can I download it?
If downloading the .iso from the website isn't working you can always hop on the Bit torrent tracker and grab it from there. Usually (in my experience) faster as well.
We ask you to wait for the official ones to come back on, if you take it from any other official source you can not be sure it does not contain malware.