Here is some info about the current status of the project.

I've made a raw signal dump from a real HP DeskJet 2130 printer.
It does not contain F3 and F5 signals and has some noise, but it's pretty readable.
Printed image: test-page-fill.png
Data: test-page-fill-data.srzip - can be opened with PulseView

PCB debugging is in progress with the following results:

First: the DC-DC step-up converter changed from FP6292IR-G1 to HX3608 since the first one did not provide enough current to initiate ink firing.

Second: some issues were found while testing the module with ESP32 MCU using this firmware

- Protection circuit on F3 and F5 signals did not function properly, its width is more than 10us

As a result, I think that the magenta color of my cartridge has been burned out since the cartridge is no more printing with magenta after my experiments on the real printer.

- Some software issues exist around every third DCLK group.

Next steps to do:
1. Temporary remove protection circuit that limits F3 and F5 width and drives all signals directly with the software.

2. Debug firmware with an in-circuit debugger.