With such a huge file, chances of download corruption increases. My first attempt was bad, but the second one worked.
Here's a collection of previous firmwares: http://www.kaser.com/ebooks.html
btw, if you're tempted to try his V5logos.zip, don't. There's a gui version at http://www.jinke.com.cn
Oh, to get thru to support, don't bother with keying the department extension. I did, and got stuck with voicemail. Just stay on the line and ask to be transferred and you'll get thru to extremely helpful people.