Recently I experienced a breakdown of the SD card on a Raspberry Pi 3 B (no B+) I use as a courtesy PC for my nieces/nephews. Since I had two SDHC 8GB cards, I did not worry too much and
- Downloaded the Raspberry Pi Imager for macOS.
- Wrote Raspbian Buster with desktop on the SHDC card (a Micro SD Kingston).
- Inserted the OS card in the Raspberry slot and installed Raspbian buster: to be sure of successful operation I rebooted the system a couple of times and it worked fine.
Then, just as a final proof-of-success, I powered off the Raspberry, turned off the power supply, waited a few minutes and then turned it on again: the system did not boot. I though it was a problem of the SDHC card therefore I repeated the same three steps, but the result was the same! So, thinking the board was damaged, I brought from my lab another Raspberry Pi 3 Model B (I never used it as I kept it as a spare part): however, after repeating the three steps above, I got the same results: the Raspberry does not boot after turning the power supply off.
After these test, I
- Formatted again the SDHC cards and repeated the three steps above by downloading directly the Raspbian buster and writing it on the cards by using balenaEtcher: same result.
- Tried to use an older Raspbian version, precisely the 2018-11-13-raspbian-stretch: same result.
- Changed the power supply (I have a couple of original Raspberry +5V power supplies explicitly designed for the Pi 3 Model B): same result.
Now, my fateful final question is: why Raspbian does not boot after seemingly having been correctly installed?