baud rate can be 9600 also

  * backup

  esptool --port COM3 --baud 115200 read_flash 0x00000 0x200000 shinewifix_backup.bin
  esptool --port COM3 --baud 115200 read_flash 0x00000 0x400000 shinewifix_backup.bin


  * restore

  esptool --port COM3 --baud 115200 write_flash --flash_mode dio --flash_freq 40m --flash_size detect 0x00000 shinewifix_backup.bin
  for 2m
  esptool --port COM3 --baud 115200 write_flash --flash_size 2MB 0x00000 shinewifix_backup.bin