Browser MIDI Troubleshooting

I am having difficulty connecting my midi device via my web browser.


Currently, the browsers that support Web Midi are:

When you are on any of the pages in the site that support directly downloading to your CODE amplifier, you will see a status bar at the bottom of the page. This will indicate whether your browser is midi-capable:

  • MIDI is not available
    Midi is not supported by your browser
  • CODE: Not connected
    Midi is supported by your browser, but your CODE amp is not connected
  • CODE: Connected
    Midi is supported by your browser, and your CODE amp is connected

You should note that Web Midi is still a draft specification, and although we've found it to be pretty stable, there could be combinations of hardware and software which have problems.

* Chrome v62 on Mac OS X:

There seems to be an issue when running Chrome v62 on Mac OSX, which prevents the firmware update from completing successfully.  If this occurs, try the following:

  • Switch your amp off.
  • Quit out of Chrome, if it is already running.
  • Start Chrome, and just open one tab for the My Marshall site.
  • Go to the Firmware Update page, and click on the button for 'Firmware Update in Browser'.
  • Switch on the amp in bootloader mode, by holding down the PreFX, Mod and Rev buttons (the first, third and fifth buttons), and then turning the power button to 'On'.
  • After a few seconds, the amp should show as connected.
  • Start the install, or reinstall, of the firmware.

UPDATE: Google have confirmed that this issue was fixed in Chrome version 63.  However, if the same issue occurs in later versions, then please try the above troubleshooting steps.

* Chrome v80 on Windows:

Chrome's MIDI configuration has changed in v80, which may cause some issues.  If you are running Windows 10, there is a setting within Chrome that allows it to use the Windows RT implementation of MIDI, which is more reliable.  However, this is turned off by default.  To turn it on, open a new tab in Chrome, and enter the following: 


You should then set the option to 'enabled', as shown below:

 ** Microsoft Edge

Note that Microsoft Edge with version numbers of 79 and above use the Chromium engine (i.e. the same engine as Chrome).  This means that these versions support WebMIDI, and will behave exactly the same as the Chrome version with the same number.

N.B. The issue with Chrome v80, and the fix to set the MIDI flag above, is exactly the same with Edge v80, except that to change the flag setting you will need to enter 'edge://flags/#use-winrt-midi-api' in the browser url box.

If you still have problems using midi from this site, here are some things you can try:

  • Check that you are using one of the browsers listed above. Make sure that the version you're using is at least the version shown.
  • Check that you have given permission for the My Marshall site to use midi devices in your browser. You will normally be prompted to do this the first time you use the site, but you can view and change the permissions later from your browser settings.
  • On Windows, only one application can use the underlying system midi driver at a time. Make sure that you're not running any other software that could be using the midi port, such as a Digital Audio Workstation or Midi Mapper.
  • If midi initially works, but you then start to have problems, close all of your browser windows, and then check that there is not a hidden instance of the browser running in the background. On Windows, use the Task Manager to do this, and on a Mac you can use Activity Monitor.
  • If all else fails, try turning your computer off and back on again! Sometimes when things crash, they can take the midi drivers with them, and the only option is to do a reboot.

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