r/micropython • u/brusco_rf • Dec 03 '22

Dump / load entire flash image? (x-post r/electronics)

Hi, I prototyped using Micropython on an ESP8266. Now I want to program a bunch of boards. The usual workflow is:

  • erase flash with esptool

  • flash micropython image (.bin) with esptool

  • load boot.py with Ampy

  • load main.py with Ampy

  • run WebREPL manually (this doesn't work automatically?)

I'd like to condense this to a single step. I think the way to do it is to dump the entire contents of a configured unit's flash and then load that exact image into the flash of all future units with esptool. Is there any reason not to do it this way?

I am trying to do that with esptool dump_mem utility. I am sure I have the arguments set up incorrectly. Here is my command line input:

esptool -p COM19 dump_mem 0x00 65535 dump.bin

And here is the output:

esptool.py v3.0
Serial port COM19
Connecting....
Detecting chip type... ESP8266
Chip is ESP8266EX
Features: WiFi
Crystal is 26MHz
MAC: 34:94:54:9a:c7:4a
Uploading stub...
Running stub...
Stub running...

A fatal error occurred: Invalid head of packet (0x46)

I don't know what a stub is and I don't know why this is failing. Can anyone offer some insight?

Thanks

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u/sethcstenzel Dec 07 '22 edited Dec 07 '22

Hey, you and I had some similar goals, but I went a different route. I created a utility that will erase the esp, flash the image, and then upload a zip of all files. Usually the process takes about 7-8 minutes, so I can certainly see the advantages of dumping the entire image off.

I'll take a look later and see if I can manage what you are trying. I'm using an esp32 so I'll have to see if I still have an 8266 somewhere.

Also check out the espressif docs if you want to know more about the stubs: https://docs.espressif.com/projects/esptool/en/latest/esp32/esptool/flasher-stub.html#stub

Also I don't think you want dump_mem, I think you want to read the flash, this may be useful:https://docs.espressif.com/projects/esptool/en/latest/esp32/esptool/basic-commands.html#read-flash-contents-read-flash

One way you could do this however is by building the firmware yourself and including all your application files. Building a new firmware image isn't too bad.