ChibiOS Free Embedded RTOS

Thanks for the reply.
Finally I just wrote my own 'driver' - very simple state machine working without any chibios I2C drivers.

Pretty much all you need to do is to create handlers for a few interrupts and use a simple state machine to handle common interrupt flags/situations.

I recommend that ...

I'm using files from Chibi_I2C_Slave_17.6.3.zip on custom board with STM32L433.
Only effect I'm able to see is the error handler working. If the transaction finishes successfully (eg. a write), data is stored in RX buffer, but RX callback is not being run.
I'm using a slightly modified example from ...