I got through all the steps mentioned in:
Until the very end. I found that “sudo dfu-util -l” was needed to get the same output as the README mentions. But then when I run “sudo dfu-util -d 1d50:607f -a 0 -s 0x08005000:leave -D core-firmware.bin”, I get the response:
“invalid dfuse address: 0x08005000:leave”
Any thoughts on what I’m missing? My spark core is currently flashing yellow, as mentioned.