GR-20: Checking the ROM Version
Use the following steps to check the ROM version in the GR-20:
1. Power on while holding the TUNER and EXP PEDAL buttons.
After a few seconds, the version will begin to flash in the display. For example, if the current version is 1.23,
[P1]/ >>> [P1]/ etc... will continue to alternate in the display.
When you're finished, turn the power off and back on again.