ESP8266 Boot

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Boot Options

                                  | GPIO 0 | GPIO 2 | GPIO 15 (MTDO)
----------------------------------|--------|--------|---------
Flash Startup (Normal)            |   1    |   1    |   0
UART Download Mode (Programming)  |   0    |   1    |   0
SD-Card Boot                      |   0    |   0    |   1


Enter Into Flash Mode

  • Most development board has auto enter into flash mode circuits, more commerial products do not really need this.
  • Pull GPIO 0 of ESP8266 before power up or reboot to enter into flash mode. -> So simply hold down GPIO 0 and press once reset will enter into flash mode manully.
  • Connect 3.3V/GND/TXD=>RXD/RXD->TXD to target, recommand USB-TTL downloader here



Boot Debug

  • Open arduino IDE, and set baud rate to 74880 on serial, can find esp8266 debug info.
ets Jan  8 2013,rst cause:1, boot mode:(3,6)
load 0x4010f000, len 1384, room 16 
tail 8
chksum 0xef
csum 0xef
csum err
ets_main.c 
  • reset causes:
   0: 
   1: normal boot
   2: reset pin
   3: software reset
   4: watchdog reset
  • boot device:
   0:
   1: ram
   3: flash

Flash Error Log

  • flash size is not correctly selected, in this case should be 16Mbit-C1 instead of 32Mbit
mismatch map 5,spi_size_map 4
system_partition_table_regist fail

Incorrect flash mode

ets Jan  8 2013,rst cause:1, boot mode:(3,7)
load 0x4010f000, len 1384, room 16 
tail 8
chksum 0xef
csum 0xef
csum err
ets_main.c
  • Fix:esptool.py write_flash 0x0 Yxxxx.bin
  • change to below, add dout SPI flash mode
esptool.py write_flash --flash_mode dout 0x0 Yxxxx.bin

Debug

Hardware Check

  • Try to swap TXD and RXD in case it is wrong
  • Buttons should be hold down or pressed firmly and properly to make the good connection, it is too tiny button
  • On module status Blue LED will blink once on reset
  • USB-TTL Compatible with 5V TXD RXD signal, for our relay boards, wiring should be 5V, GND, TXD and RXD. Recommanded USB-TTL debugger boards are CP2102, speed up to 15000000 (Some other boards only do 115200)

Software Correct Boot Mode Output

  • Correct flash mode output on arduino baudrate 748800:
ets Jan  8 2013,rst cause:2, boot mode:(1,7)
  • Correct normal boot mode output
 ets Jan  8 2013,rst cause:2, boot mode:(3,7)