Mu-so Gen 2 — forced USB firmware update procedure

Mu-so Gen 2 — forced USB firmware update procedure

Overview

This article is for Westan agents and authorised service agents. It covers the Mu-so Gen 2 forced USB firmware update procedure, including the complete file set required and the most common error (missing the forceupdate.naim file).

When is a forced USB update needed?

  • OTA firmware update via the Naim App has failed or is stuck
  • The unit has a firmware version that is causing functionality issues and OTA will not apply the fix
  • The unit is partially responsive but cannot complete a normal App-initiated update

Required files — all three must be present on the USB drive

A forced firmware update on the Mu-so Gen 2 requires exactly three files on the USB drive. Missing any one of them will cause the update to fail silently.

  1. The main firmware binary file (e.g. MuSo2_X.X.X.bin or similar — confirm filename with Naim UK)
  2. A secondary firmware or update manifest file (confirm with Naim UK)
  3. forceupdate.naim — this is the most commonly missing file and is required to trigger the forced update process. Without it, the unit will not begin the USB update even with the other files present.

Westan can supply the forceupdate.naim file — contact naim.support@westan.com.au to request it.

Procedure

  1. Format the USB drive as FAT32
  2. Place all three required files in the root directory of the USB drive (not in a subfolder)
  3. Power off the Mu-so Gen 2
  4. Insert the USB drive into the USB-A port on the Mu-so Gen 2
  5. Power on the unit — it should automatically detect the update files and begin the forced update process
  6. Do not power off or remove the USB drive during the update
  7. The unit will restart automatically when the update is complete
  8. Verify the firmware version in the Naim App after restart

If the forced update does not begin

  • Confirm the USB is formatted FAT32 (not exFAT or NTFS)
  • Confirm all three files including forceupdate.naim are in the root directory
  • Try a different USB drive (some drives are not recognised by Naim products)
  • If the unit still does not begin the update, contact Naim UK for updated file set or further guidance

Key contacts

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