I am going to take a look at this today.  I wrote / modified a program to help restore the pic firmware on an L3+ ( https://github.com/darval/bitmain-tools ) and I am going to see if I can modify it to work for a T9+.  The pic is a microcontroller on each hash board.  Usually when it (bmminer) tries to get the version and it fails (-1 or 0xff), it means the pic firmware got trashed.  My program has a mode to try to restore it.  It currently doesn't work on the T9+, so don't try it yet, but if I am successful, I will update it and post about it here.  Then you can try it out.  Like anything, this stuff is all use at your own risk.