[RB zero 2] Board not responding to i2C

[serlecu]

Describe the bug
I'm using your library from a raspberry Zero 2. The i2C port is running (tested with lo-fi) osciloscope but the Grove board is not reacting (no led activity nor motors).

To Reproduce
Board is powered with 12v 3A PS
Raspberry has Bullseye OS
Also has a Hyper-Pixel 2Round display HAT that provides a i2C interface with interrupt and 3.3V
(I2C interface is activated in raspi-config and mirrored with the Hyper-Pixel recommended tecnique sudo ln -s /dev/i2c-11 /dev/i2c-1 )
Running python DC motor example.
(I tried without Grove's jumper and powering the i2C port with the raspberry's 3.3v, but also without the 3.3v and the bridge that provides 5V from the board).

Any ideas?