Ah, ok yes, version 3.3 top board does have a 24C02 EEPROM, but it’s only used in order for the firmware to distinguish between versions 3.2 and 3.3, it’s not used to store any data. What’s going on is that 3.3 and 3.2 are otherwise the same except the pin ordering for the wired Ethernet jack are different (3.3 is for W5500 module and 3.2 is for ENC28J60 module). Without any ‘signature’ the firmware will not be able to tell these two apart. So I added a very cheap I2C EEPROM as a way for the firmware to detect which version it is. There are no other spare GPIO or analog pins for this purpose. So an I2C chip would be the easiest.