To install a firmware update on the Mastermind GT, you need a USB flash drive and an update file.
NOTE!!! Please remember to back up your settings before performing a firmware update. If you have to revert back to an earlier firmware version, the GT may factory reset, losing your settings.
Select a flash drive
The flash drive included with your GT will certainly work, and most off-the-shelf flash drives will as well. For best results, stay away from very large drives (greater than 64GB) and USB 3.0 drives. The drive should be formatted as FAT, which is the Windows format. This can be done on any Windows PC and it can also be done on Macs using Disk Utility. As of the 4.0 firmware release, the GT can also format a flash drive. Enter setup by holding the 1 and 3 buttons, then select System Functions, followed by Format Drive. Insert the flash drive when prompted, and it will be formatted for you.
Copy the settings file to the flash drive
Download the latest firmware file from the Mastermind GT page. If the downloaded file is a ZIP file, double click it to extract it. Now, plug the flash drive into your computer and copy the firmware file, which ends in .rjf, to the drive. If there are any other firmware files on the drive, remove them now to insure that the correct file is loaded. Eject the flash drive: right-click (or Ctrl-click on a Mac) on the flash drive icon on your screen and select Eject.
Perform the update
Power up the Mastermind GT holding the two small buttons under the main screen. The Mastermind GT Bootloader screen should appear. Plug the flash drive into the GT and the update process should begin. Don't remove the flash drive until the GT finishes updating and returns to the normal operating mode.