I have had my EHP-606 for almost a year now...and only brought it because Elektron promised DTS downmixing shortly after my purchase. Well since they have not held up to their end of the deal I have cross flashed my 606 with the popcorn hour firmware.
DTS downmixing is working perfectly now...the only downside is the remote for the device does not work anymore. This is still ok because I use a logitech harmony 550 remote anyway. I programmed for the popcornhour A-110 and all is well.
Here is a link to the thread that shows how to cross flash the fw...http://www.mpcclub.com/forum/showthread.php?t=19334
there is a link in the first post that will provide instructions and downloadable files.
Good luck and screw Elektron!!!