Hyperpixel 4.0 ceased to work

I have a Hyperpixel 4.0 Rectangular Touch display mounted to a Raspi 3B+.

After installing the driver curl -sSL https://get.pimoroni.com/hyperpixel4 | bash to that (latest-greatest) Raspbian Buster it worked fine for some days, but suddenly it ceased to work without me changing anything.

Reinstalling that driver again didn’t help. I checked and I can still control the backlight either on or off and also via GPIO19 PWM I can dim it - which makes considerable amount of noise but works.

I also tried to install it to a new Raspi and new also new Buster installation, but same issue…

Any hints what to try next?