I just had luck using AXEII as midi device,axe edit open but sending the sysex with MIDIOX (256/15,128/16,check "delay after f7")
Only had MFC midi in cabled to AXEII midi out,unplugged 8 pin/ethernet and used power supply
pretty much just like YEK told me too.....axe edit probably didn't need to be open but it was
Grab a beer and try it!
Yeks MFC-101 How-Tos page - Fractal Audio Systems Wiki
"To upgrade using the Axe-Fx II as a USB-to-MIDI MIDI adapter: Source
Connect the Axe-Fx II to your computer, through USB.
In the Axe-Fx II's MIDI menu, set SendRealtimeSysex to NONE, and UsbAdapterMode to ON.
Power down the Axe-Fx II.
Connect the Axe-Fx II's MIDI-OUT to the MFC-101's MIDI-IN with a 5-pin MIDI cable.
Power on the Axe-FX II.
Power on the MFC-101 by reconnecting Cat5 cable, while holding down footswitch 1 (enters firmware update mode).
Send the new firmware with a MIDI librarian, such as MIDI-OX or SysEx Librarian, from your computer to the Axe-Fx II.
Power down the MFC-101 and Axe-Fx II.
Remove the MIDI cable.
Power on the Axe-Fx II.
In the Axe-Fx II's MIDI menu, set SendRealtimeSysex to the desired value, and UsbAdapterMode to OFF.
An upgrade may require you to reset the MFC-101 to its factory settings. If so, it will be stated in the release notes. To reset the MFC-101, power on while holding switch #11. Note: this will cause you to lose your configured settings! You can save these on forehand and restore these afterwards.
MIDI utilities may 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.
If you're experiencing problems, open the Utility > Preset page on the Axe-Fx, because this makes sure the Axe-Fx is not sending out stuff which could interfere with the update process."