I spent about 3 hours yesterday fixing the problem of the eternal flashing green light, not knowing the reason it had come to be. After getting it working I had a few hours of fun running LEDs from a LiPo. After the battery ran out of juice, I recharged it and plugged it back in and I had the eternal green flasher again. I was ready to throw it all in the bin.
Luckily this morning I found this thread, re-flashed it and all is working again.
Perhaps the issue should be a little better publicised to save others from dispatching their Sparks prematurely. Ultimately a fix would be nice, pretty please 