(Important information, more detail at the end of this post - if I do the same thing on the mainboard with 2 function slots, it works in function slot zero).
I run into the exact same issue the user @avsteele descibed in this unsolved thread from 2023:
I have bought both components new in April 2025 and set them up just how it is described in the hookup guide MicroMod Ethernet Function Board - W5500 Hookup Guide
As Board definition I tried:
- vanilla ESP32 in Arduino 2.3.6
- Espressify ESP32 (https://espressif.github.io/arduino-esp32/package_esp32_index.json
- Arduino Sparkfun boards)(https://raw.githubusercontent.com/sparkfun/Arduino_Boards/main/IDE_Board_Manager/package_sparkfun_index.json)
Initially I used the second board definitions from Espressify Github and flashed the test script from the hookup guide. It did lead to the issue right away.
I’ve tried using the other 2 board definitions, same result.
When I remove the PoE-Ethernet and/or use the Wifi+Bluetooth Micromod Module, everything works fine.
I have attached screenshots of the flash and boot process. Notice that when the flashing fails, the flash memory is not detected properly and set to 4MB (instead of the correct 16MB), maybe that is important. Manually setting 16MB does not help though.
I’ve also tried several variants, like flashing with or without PoE supply, did not help either.
I’ve noticed that in the Ethernet hookup guide, in the hardware overview it says:
" WP OPEN Pulls EEPROM Write Protect pin to 3.3V/HIGH Close to pull this pin to 0V/LOW to disable write protect."
Is that related to the issue?
ALSO I have another mainboard with 2 Micromod ports.
When I insert the ESP32 and the PoE-Ethernet here into Function Zero, IT WORKS.
If I insert the PoE-Ethernet into Function One, I get the same error as described above.
