I am currently trying to flash ESP8266 EP-01 so it can connect to Firebase, but I keep running into issues. The code currently requires FirebaseArduino library which uses Json5 so I already downgraded that library. However, when uploading I keep getting multiple errors. The code begins to upload but after connecting, I get the following error:
File "C:\Users\jeffr\Documents\ArduinoData\packages\esp8266\hardware\esp8266\2.6.3/tools/upload.py", line 65, in
esptool.main(cmdline)
File "C:/Users/jeffr/Documents/ArduinoData/packages/esp8266/hardware/esp8266/2.6.3/tools/esptool\esptool.py", line 2890, in main
esp.connect(args.before)
File "C:/Users/jeffr/Documents/ArduinoData/packages/esp8266/hardware/esp8266/2.6.3/tools/esptool\esptool.py", line 483, in connect
raise FatalError('Failed to connect to %s: %s' % (self.CHIP_NAME, last_error))
esptool.FatalError: Failed to connect to ESP8266: Timed out waiting for packet header
esptool.FatalError: Failed to connect to ESP8266: Timed out waiting for packet header
P.S. I attached my code as well but I have removed the 4 fields for privacy purposes 
Firebase_Arduino.ino (1.77 KB)