you don't have to flash the firmware. you need to adjust the eeprom settings.
Setting of EEPROM-cells/ Werte in den EEPROM-Zellen 00 ¡ª I2C address setting cell of the connected display. The port extension board for display 1602 made on the PCF8574AT chip has the address 7E, on the chip with the ¡°T¡± index - 4E. OLED displays usually have an address of 78 or 7A. It is allowed to record any address in the cell for normal operation with the connected I2C device. The default value is 4E, which corresponds to the LCD display 1602 with an extension board with the PCF8574T chip. OLED-Display= set 78?
73 Ton PA0ARR
