Just a fresh bump here as I needed to look up how to do this again and I encourage everyone to always backup 
Here’s a better description:
If you want to back up ALL your sounds, make C6 receive sysex, on the A4/K go to the SOUND MANAGER, tap a trig so that all the trigs light up and you can see all banks (or just tap one bank if that’s all you want), click right, click SELECT ALL, then scroll down to the bottom and click SYSEX SEND.
Now save it in C6 and you’re golden.