That’s not what this is about. ESPHome (or any other user uploadable firmware) replaces only a part of the code running on your ESP. There’s a second part that you cannot replace or access. It manages the wifi part of the device, the wifi stack, the radio packet control, etc. You have no access to this code.
There are some legal reasons for this. In order for manufacturers to get FCC approval, some of the lowest level code (the one that manages the radio) is required to be non-user modifiable. If users modify it, the device loses compliance. But that does not mean that this code has to be closed source or undocumented. And it also doesn’t mean that the wifi stack (the code that manages the TCP/IP layer) can’t be replaced. Yet all that is closed in ESPs and Espressif hasn’t documented anything around this. Who knows what is in that stack. Maybe a backdoor. Since the code is not open, noone but Espressif knows.
Or users who know exactly how they work and could build their own if they wanted to, because creating embedded HW and SW is an important part of their daytime job (someone like, you know, me for example), but who just don’t want to spend the little free time they have on that and are perfectly happy to use a well build off the shelf device. There is absolutely nothing wrong with using off the shelf devices, even if it’s only about aesthetics and WAF.
Had you read any of the links I posted, you would know
Until you posted the links, I had no clue what Fibaro was. That was my point.
No. The build from IDE contains the Espressif Arduino Core for ESP8266
This is from the Expressif site: "Many efforts around the ESP8266 Arduino Core make it worth the effort to use it over the stock SDK, besides simply being as open source as possible. Arduino Core includes C++ classes for a web server (SSL/TLS available), a filesystem implementation, and both a DNS and mDNS server. Client tools for communicating over TCP/IP, including an implementation for making HTTP requests, are also provided."
Since the Arduino code is open source, you do have access to this code.
No. This is just a higher level tool collection and connection layers eventually linking to the ESP NONOS SDK which contains the low level binary components. Even the lwIP-2 linklayer used by the Arduino Core is just a connection layer to the NONOS SDK. Their RTOS SDK provides some more tools with source, but again it ends with the binary low level drivers. See their 8266 SDK docs, chapter 1.4:
ESP8266 FW (Firmware) has been provided in binary format files (.BIN) that can be
downloaded directly to the HDK.
That binary FW contains the actual low level code.
