Is there any chance that using a Chinese version of the config tool would make a difference? I had some l luck a year ago when I purchased some Dahua cameras from Ali Express. Upgrading the Eng firmware seemed to brick my cameras, until I tried switching from the English config tool and using the Chinese version (the gui buttons were all in the same place). I'm not sure why, but the Chinese configtool solved my problems.
I posted on Cam-It at the time. Not sure I helped anyone though. Just in case, I wanted to share.
http://www.cam-it.org/index.php?topic=6510.msg40893#msg40893
I got a 404 error trying to access camera, so I turned off power, restarted, and the camera showed up fine, no problems. So I tried installing the firmware again, and it failed again. Except this time, the camera was not fine. I could not access it by IP address, it gave me a blank white page "Error 404 Not Found" that came from the camera. No matter what I tried, it seemed totally bricked.
But then I tried this Chinese tool I have, basically the same as my other Config Tool, so I was able to guess at the Chinese buttons. It was able to connect to the camera, install the new firmware, and fixed the entire issue! Everything is back to normal for me, and my camera has the new firmware installed.
So I'm wondering, did I just get lucky, or do I have some magical Chinese tool that overrides regional settings or something-- that can help out other people who bricked with wrong firmware? What I used is called General_ConfigTool_Chn_V1.06.0.R.120628