ESP8266 Community Forum

I am using Arduino IDE 1.8.5.
I have successfully compiled my sketch. It fails to upload to my Huzzah ESP8266.
1. I changed the upload speed to 9600.
2. I held the GPIO0 button, depressed the Reset button.
3. I am using a FTDI cable to communicate with my PC, running Arduino's IDE.
4. I have even used an extra ESP8266, with no jumpers or other components connected.

In the past few weeks I have been successful developing, compiling and uploading this sketch to one of my Adafruit Huzzah ESP8266 micro-controllers. Today I made a few modifications to the sketch and tried again to compile and upload it.

The "verbose" upload data is as follows:

Arduino: 1.8.5 (Windows 10), Board: "Adafruit HUZZAH ESP8266, 80 MHz, 4M (1M SPIFFS), v2 Prebuilt (MSS=536), Disabled, None, 9600"

Sketch uses 263059 bytes (25%) of program storage space. Maximum is 1044464 bytes.
Global variables use 34796 bytes (42%) of dynamic memory, leaving 47124 bytes for local variables. Maximum is 81920 bytes.
C:\Users\JMK\AppData\Local\Arduino15\packages\esp8266\tools\esptool\0.4.12/esptool.exe -vv -cd nodemcu -cb 9600 -cp COM8 -ca 0x00000 -cf C:\Users\JMK\AppData\Local\Temp\arduino_build_494748/ESP_ADS1015_HTTP_DS.ino.bin
esptool v0.4.12 - (c) 2014 Ch. Klippel <ck@atelier-klippel.de>
setting board to nodemcu
setting baudrate from 115200 to 9600
setting port from to COM8
setting address from 0x00000000 to 0x00000000
espcomm_upload_file
espcomm_upload_mem
setting serial port timeouts to 1000 ms
opening bootloader
resetting board
trying to connect
flush start
setting serial port timeouts to 1 ms
setting serial port timeouts to 1000 ms
flush complete
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
read 0, requested 1
trying to connect
flush start
setting serial port timeouts to 1 ms
setting serial port timeouts to 1000 ms
flush complete
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
espcomm_send_command: receiving 2 bytes of data
espcomm_send_command: receiving 2 bytes of data
espcomm_send_command: receiving 2 bytes of data
espcomm_send_command: receiving 2 bytes of data
espcomm_send_command: receiving 2 bytes of data
espcomm_send_command: receiving 2 bytes of data
espcomm_send_command: receiving 2 bytes of data
espcomm_send_command: receiving 2 bytes of data
Uploading 267200 bytes from C:\Users\JMK\AppData\Local\Temp\arduino_build_494748/ESP_ADS1015_HTTP_DS.ino.bin to flash at 0x00000000
erasing flash
size: 0413c0 address: 000000
first_sector_index: 0
total_sector_count: 66
head_sector_count: 16
adjusted_sector_count: 50
erase_size: 032000
espcomm_send_command: sending command header
espcomm_send_command: sending command payload
setting serial port timeouts to 15000 ms
setting serial port timeouts to 1000 ms
espcomm_send_command: receiving 2 bytes of data
writing flash
................................................................................ [ 30% ]
................................................................................ [ 61% ]
................................................................................ [ 91% ]
..................An error occurred while uploading the sketch

What could my problem be? Thanks for your assistance.

IMO this has been discussed many times - rise the serial speed at least to 115200 and try again.