This printhead suddenly can not be recognized by the Canon printer model Pixma IP4300. I suspect the PCB. I cleaned it thoroughly and I will test it tomorrow in the office BUT I am pretty sure that it will not work as it wasn't a matter of cleaning as the printer does not recognize it at all (orange led flashes 5 times and according to Canon it is a printhead malfunction).
Just buy a new head. You need QY6-0061-000. Try at all cost to get an original, unopened original Canon one. A remanufactured one may or may not work, as Koray explained.
I have never heard of any method to revive a dead printhead.
I suspect that a flash memory is hidden on the other side of the PCB -which may be used as a printing counter for a planned obsolescence
Planned obsolescence is 99+% myth. These printheads do not have a "self destruct" function, in fact, I don't believe the heads have any kind of memory at all. (The ink tanks do, but only for checking authenticity — Canon inkjets allow you to continue printing after the printer has warned you the cartridge is empty.)
FWIW, I'm still using a Canon MP970 (same generation as your iP4300, uses the same cartridges).
or in the best case, a passive component that may be burned, so it could be easily repaired.
Nope. There are no passives, as Koray said. Thermal inkjet printheads are in fact large ICs, so all the support circuitry in the head is actually in the same piece of silicon as the nozzles. (It's pretty much just driver transistors and decoders and shift registers, so that thousands of nozzles can be controlled with just a few dozen signal lines.)