I had the same problem (red solid light) I've tried with 2 different SD cards, formatted as FAT, FAT32 nothing worked. Until I try one last time with a simple 'Hello World' script and saved the file as inject.bin. It seems that saving the file as inject.bin fixed the problem, I was using different name for my scripts. It sounds silly, but as soon as I did that I got green blinking light and script executed in Windows 10 machine, you can check that just in case.