The dual extruder is still being worked on.
I installed the latest 2.x universal firmware as mentioned here. I have a Taz6 with the original single extruder. What should I pick out of the choices? none seem to have the exact e-steps (830) on the back of the tool-head. The closest one is the “Standard” .5mm which has E-steps set to 814. do I just use that or adjust it to 830?
Probably best to use the e-steps on the back of the tool-head. Even better would be to run a calibration and use the calculated value. Search this forum for “e-step” and “calibrate” and you should find detailed steps to follow.
Is it only Taz 6 for the universal firmware or does it work on Taz 5 also?
There doesn’t appear to be a version of universal firmware for the TAZ 5.
I had success today updating my TAZ6 to 2.0.9.0.13 added by 2.0.9.0.13 for the TAZ6 and Workhorse (65cc7ed1) · Commits · LulzBot 3D / Cura-LE / Cura Binary Data · GitLab using OctoPrint with these settings

I had to install avrdude while SSH’ed into my octopi with
sudo apt install avrdude