ESP8266 Community Forum

I would just remove the shield and desolder/replace the flash, that's it.

Yes. Of course you can't stop determination. It's all about degree of difficulty.

The book on hacking the original X-Box shows the lengths some will go to. https://bunniefoo.com/nostarch/HackingTheXbox_Free.pdf

Replacing whole ESP module is even easier than replacing the flash which would be beyond quite a large number of people. One could also embed the can in resin to make it more difficult.

The product I’m producing is made on a small scale, on demand. I’m looking at selling a base model which is not user flashable, and a “developer” model that the user can flash. I am exploring various ways to monetize the product. The sale of the base model alone is not a sustainable business.

The device does a specific job that is served by the base model, but users may want any number of customizations made to the firmware for their use case. In that case they could hire me as a consultant, or purchase the developer edition to develop their own firmware.

I don’t think I need military grade security here - if users want to swap modules I suppose that’s their prerogative. But I wouldn’t be offering warranties on tampered hardware. I’m looking for “good enough” security that acts as a deterrent.

Use an esp8285 on your own multilayer pcb with the programming pins brought to an edge connector via middle layer.
Cutting/breaking off the edge connector leaves the programming pins fairly unaccessible once esp8285 is covered in resin.