The 24LC256 EEPROM chip needs to be formatted correctly for use with the MB firmware.
Upload the following firmware to the Atmega processor: Groovesizer_ALPHA_EEPROM_INIT_001
CAUTION: formatting the EEPROM will erase any patches and patterns currently stored on it.
After a moment, the Groovesizer will start scrolling through the alphabet from A to Z and the numbers 1 to 9 on the LED grid. This is an indication that the EEPROM has been formatted successfully.