Use a USB-to-TTL Serial Adapter or another ESP device to connect to your ESP8266 with this wires :
Pin Wiring Diagram
Power on the ESP8266 while holding GPIO0 (Flash) connected to GND
This puts the device into flash mode
Execute backup.sh and follow the process until completion
If the read operation fails (common with dupont wiring), unplug and replug the ESP8266, then retry extracting the chunk (just press enter)
In some cases (but not 100%), use fix_backup_order.py to correct the order of the backup chunks
To reflash the ESP8266 with your backup:
- Connect the ESP8266 using the same wiring as for the backup
- Run the following command:
esptool.py --port /dev/ttyUSB0 --baud 115200 write_flash 0x00000 yourbackup.bin