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.
Fender Mustang firmware version 1.10 is the current version of Mustang firmware.
There are various fixes and enhancements in this version including but not limited to:
● Moved EXP-1 expression pedal Volume mode (Mustang III-V) control to adjust volume level after the Amp section but before the Post-Amp Effects section.
● Added press-and-hold EXIT+TREB functionality to control MID on Mustang I/II amps.
● Improved rejection of accidental/unintended effects knob changes on Mustang I/II.
● Revised how EXP-1 expression pedal calibration is performed (Mustang III-V). The new procedure will provide users with added flexibility to customize the range of their pedal, i.e. they can throw away some heel range to get more toe sensitivity.
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.
Note that a Factory Restore also initiates the expression pedal calibration process.
This firmware update is recommended for all Fender Mustang I-V (V.1) amplifiers.