I have connected M24C02WP eeprom (i2c) using prototyping board to UEXT1. SDA to pin 5, SCL to pin 6. E0, E1, E2, WC are connected to GRND pin. It's powered from board too. But it doesn't work at all. Oscilloscope shows that level is always high with some fluctuations when Chibios tries to change state of line.
Why M24C02WP isn't compatible with STM32-LCD?
It is the other way around - pin #5 of UEXT1 is SCL, pin #6 of UEXT1 is SDA. Refer to the schematic here: