05-20-2020, 06:26 PM
You haven't mentioned trying to see what is going on using a serial cable. That would tell you, I think, whether uboot was starting up at all. If you don't have one, you might try removing the emmc and throwing the switch and pressing the reset button, then trying to boot from a good sd card. It;s just possible that something is messed up with uboot on the emmc, (I am assuming that you are not running u-boot from SPI flash) so that the system never gets as far as lighting an led.