Below are instructions on how to update the firmware on your Reverb. Attached are the firmware files and the changelog.
How to upgrade your Reverb's firmware
1) download the firmware file from below. If you want to use the beta firmware, which has more features, but isn't as tested, download the .bin file with the higher version number. The production firmware has a lower version number. If there's only one .bin file, there is no beta firmware at this time.
2) copy the file to the root directory of a high-capacity SD card that's been formatted FAT32.
3) insert the SD card then power on the pedal.
4) The preset LEDs should marquee yellow for a bit, then all turn green when the update is complete.
5) remove sd card, cycle the pedal's power, and you're good!