NodeMCU backup sketch

Question

Is it possible to extract a backup of the sketch uploaded to a NodeMCU (as I know that it is possible to backup the firmware).

If so, using which tools?

• Chad G: is your goal just to have a backup of the hexcode, or actually de-compile it back into C/C++?
• Juraj: esptool is THE tool for esp8266

Answer 1

esptool.py is 'avrdude' for the esp8266. it can read the flash too. but you must know the addresses. tha first copy of the application always start at address 0x1000. the length of the application area depends on the size of the flash and the size of the SPIFFS.

> esptool.py read_flash -h
usage: esptool read_flash [-h] [--spi-connection SPI_CONNECTION]
 [--no-progress]
 address size filename
positional arguments:
 address Start address
 size Size of region to dump
 filename Name of binary dump
optional arguments:
 -h, --help show this help message and exit
 --spi-connection SPI_CONNECTION, -sc SPI_CONNECTION
 ESP32-only argument. Override default SPI Flash
 connection. Value can be SPI, HSPI or a comma-
 separated list of 5 I/O numbers to use for SPI flash
 (CLK,Q,D,HD,CS).
 --no-progress, -p Suppress progress output

• tony gil: i was under the impression that the same tool that i use to flash (firmware) would be the one to get this job done. tks 4 confirming and indicating which options to use and how to use them. UPVOTED, ACCEPTED. :)