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Updating firmware on Fender® Mustang™ I-V (V2) Amplifiers

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How can I update firmware on Fender® Mustang™  I-V (V2) Amplifier?

Your Fender Mustang amp's firmware can be updated by the user with the Fender FUSE software and your amp connected. To do this, please follow the steps below.

  1. Go to the Main Menu (top left hand side in the Fender FUSE user interface), and select Utilities and Update firmware.
  2.  Turn off the power on your Fender Mustang amp. While holding the Save button (the Data Wheel on III, IV, & V),  turn the power back on.
  3. A dialog window will open. Here you will choose either the bundled firmware update file or you can browse for the firmware file you would like to update to. (The current Mustang firmware version can be downloaded below)
  4. Once you have selected the correct firmware file, select it, and Fender FUSE will automatically begin the firmware update process.
  5. Once the firmware update is complete, turn your Fender Mustang amp off and back on. At this point, the update process is complete

Note that a Factory Restore will require that the Explession pedal (EXP-1) if used will need to be recalibrated. Please see the instructions below to recalibrate your EXP-1 pedal.

The EXP-1 expression pedal calibration procedure is as follows:

1. Press and hold UTIL while powering on, UTIL LED should light up for 1 second.
2. Move the expression pedal between the desired heel and toe endpoints to set the range.
3. Turn the encoder knob to the next Preset to complete the process.


Fender Mustang firmware version 2.2 is the current version of Mustang firmware.

There are various fixes and enhancements in this version including but not limited to:

●  Corrected behavior of HiQ control setting in Touch Wah and Pedal Wah effects.
●  Improved responsiveness to Rate control changes in the Step Filter effect.
●  Improvements to Small Hall, Large Hall and Room reverbs (maintained stereo reverb output).
●  Revised LCD contrast factory default setting and control range.
●  Known issues: None.


Fender Mustang firmware version 2.1.

There are various fixes and enhancements in this version including but not limited to:  

●  Added Utility Menu item to configure the Effects Loop insertion to better facilitate looper pedal usage. There are two options: Normal and Looper Pedal.
-Normal: effects loop is inserted after the internal effects that are located post amp modeling.
-Looper Pedal: effects loop is inserted after the speaker cabinet simulation if the headphones are not connected, and after the headphone cabinet simulation if the headphones are connected.
●  Minor adjustment to the ’57 Champ and 4x12V cabinet simulation to more closely match the modeled cabinets.
●  Known issues: None.

Note: This firmware is compatible with Fender Mustang I-V (V.2) amplifiers and requires that Fender FUSE™ version 2.7.0 or later be installed. Please see the "Related Downloads" section below to get the Mustang V.2 version 2.1 firmware and the Fender FUSE version 2.7.0 software.


The Fender® Mustang™ I-V (V.2) Amplifiers feature the following new amp models and effects.

New Amp Models

  1. “Fender ’57 Twin”
  2. “British Watts” 
  3. “British Colour” 
  4. “‘60s Thrift” 
  5. “Stereo Preamp” – from the Mustang Floor: linear, flat eq


  1. Diatonic Pitch Shifter – new pitch effect providing diatonic harmonizing capability
  2. Improved Chromatic Pitch Shifter (stays in tune better, less warble)
  3. “Greenbox” - 
  4. “Orangebox” 
  5. “Blackbox” 
  6. “Big Fuzz” 
  7. “Ranger” 
  8. From the Mustang Floor: Touch and Pedal Wahs are available in both Stomp and Mod categories.

Additional enhancements to the Mustang (V.2) Series include:

  • Enhanced Headphone/Recording Speaker Cabinet Simulations (“higher definition”, same as with the Fender Mustang Floor)
  • (Mustang III-V / V.2 only) New EXP-1 Control Screen (press and hold the encoder to access EXP-1 configuration menu)
  • (Mustang III-V / V.2 only) New 2-Button Footswitch Modes – Mod/Tap, Dly/Tap, Rvb/Tap, Mod/Dly, Mod/Rvb, Dly/Rvb
  • (Mustang III-V / V.2 only) New 4-Button Footswitch Modes – Normal, Mode1 Lock, Mode2 Lock, Mode3 Lock