I had the same thing happen until I did this:
Note on MIDI utilities: many MIDI utilities need to be configured to work "slowly" in order to perform a successful upgrade. For example, in MIDI-OX set Low Level I/O Buffers to 256 or 128 (size) and 16 (number), Milliseconds Between Buffers to 60 ms, and make sure the Delay after F7 setting is ticked. Use View > Sysex to bring up the Sysex view window, then go to Sysex > Configure to configure the buffers. Also verify that the options MIDI FIlter and Pass Sysex are ticked.
MArk