Be very careful with that HEX file. It is only supposed to be used on the T9+. See quote below from that thread:
Also beware, my HEX file is ONLY for the T9+ ! it is equipped with a PIC32 while all other antminer are equipped with PIC16 !!!
Again, like I mentioned earlier, if you can't use the April firmware to fix your issue, you should unplug the chain/board giving the error, flash the same firmware through the web "Upgrade" page, let it boot, then plug the board back in and reboot. Seems to work consistently.