I thought I'd see if I could set up my H6 again for Jamkazam, this time on an old Dell Latitude E5430 laptop that I made into a Hackingtosh running 10.12.6 Sierra OSX and I got it working fine pretty quick so this is what I did step by step....
1) With the H6 batteries taken OUT I plugged it into a spare USB port and powered it up to use the laptop USB power
2) I then selected Audio Interface as the mode and then Multi Track (but you can use Stereo Mode as well)
3) Selected PC/Mac (not PC/Mac using battery power)
4) Opened Jamkazam (this updated to v 1.0.3673), logged in and then clicked to create a solo session
4) I was then advised to set up my device so I then went to 'Add New Gear'
5) On the Select & Test Audio Gear I clicked Resync just to ensure the H6 is properly detected
6) Selected H6 from the drop down and then the test run automatically which showed 10.27ms latency and a I/O rate of 400 and 0.18 variance
7) Set up the tracks accordingly and was ready to jam
If you're Windows based you will need to install ASIO4ALL BEFORE you do anything else otherwise Jamkazam will never see the H6. You can download that from
http://www.asio4all.org/
Also some USB ports can be a bit fussy so try another one on your computer if the above doesn't work for you
Hope that helps