Can't flash ESP8266 anymore (NodeMCU)
The fix ended up being to use a 220ohm resistor between D3 and GND (It has been pointed out, though I haven't tested it, that just wiring D3 to ground on startup should have the same effect). Then unplugging the USB cable, plugging it back in, then flashing the blink program to test. That got it going. I tried a 10kohm resistor too per some documentation I read but that didn't end up working. Wanted to post in case someone else stumbled on this issue. 

Source

GitHub Issue

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