- Low/bad powersource
- Missing pullup resistors on GPIO0 and GPIO2
- Connected USB / RS232 converter without its own power supply.
I reprogrammed ESP8266 at least a thousand times and the flash is still good.
After all, the author of the article you mentioned, has it already appealed.
At the moment I can say that with the Arduino / ESP8266 I have the perfect reliability and I have absolutely no problem with the recording of sketches.