rPi4 no longer capable of HDMI output. Eeprom recovery did not help

I have a rPi 4 that died on me, in two stages:

• First it would only show a yellow screen on HDMI outputs.
• Then later, it completely stopped outputting HDMI altogether. It seems to be in a reboot loop?

Things I have tried:

• Replaced power supply.
• Replaced monitor.
• eeprom recovery using Ubuntu imager utility to write SD card.
• eeprom recovery using Mac OS imager utility to write SD card.
• eeprom recovery via manual copy of eeprom recovery files to FAT SD card.
• Tried both HDMI output ports (neither shows physical damage.)
• Created new OS image.

What else can I try before I scrap this unit, and order a new one?

The rPi has been working just fine for a year or so, before this happened out of the blue.

plot-twist: It was a faulty HDMI cable. Apparently they can break down with normal use.