I have a Raspberry pi 4 model B, have been using it for more than a year. A few days ago it started having problems. After 10/20 seconds from startup it gives an error pattern that looks like 1 short and 1 long blinks on the ACT led.
I haven't found a reference for that error and don't have an adapter for the display. I've tried cloning the microsd and a fresh raspbian install but the problem persists.
Here's a video of the pattern: Google Drive