Arduino can't Uploaded a new sketch on ESP8266

I have uploaded a lot programs by arduino on ESP8266 but now when I want to uploaded a new program, It has some error like below, although before program still working on it, but I can’t uploaded a new program on it.
Very thank you.


esptool v0.4.9 - (c) 2014 Ch. Klippel <>
	setting board to ck
	setting baudrate from 115200 to 115200
	setting port from COM1 to COM4
	setting address from 0x00000000 to 0x00000000
	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