I have this same exact issue. Tried all the fs combos and reset it multiple times..The only way to I was able to get input back is to leave it on a while with hx edit open.
This is obviously not ideal...
Spoke to L6 support and they pushed me to Yorkville which has subcontractors at local music stores. I will visit on of these tomorrow and see what they say.
Will post an update, hopefully with good news.