The letters written on the card reader slot (with marker) are different depending on which stepper driver it has. These are for the ones 4.2.X board with STM32F103RET6 controller: C = HR4988 E = A4988 A = TMC2208 B = TMC2209 H = TMC2225 Information obtained from 3DPrima.
In this video, we cover how to clear/store settings in the EEPROM, adjust acceleration values, and change TMC driver settings for our EZBoard all from the LCD!