Slightly tasted the materiel.
RTOS is an operating system consisting of one kernel (and a loader). There is no such thing as an “executable file format”, there is no shellexecute (). You write everything in main (), collect, flash. In principle, loading code from a file can be fastened, like a script interpreter, and a java machine.
The sources that are lying on sourse are more like a school project. Maybe something reversed by amateurs. The documentation is zero. It is loaded only from the flop, the rest of the bootloaders are incomplete. The kernel starts the built-in shell, in which half of the teams are not finished. A very limited set of drivers, there is no network support at all, and drivers can be called conditionally. In general, something tells me that this is some kind of wrong Nucleus.

I have not dumped the firmware from my body yet.

I look at the photo and mentally stand on the position of a mad professor from the movie “Back to the Future”.

"To the future? And why, I was already there ... "(c) from the 3rd part.

Looking bad :)
Perhaps you should do something like this:
1. To study RTOS, download, try to build, run in a virtual machine.
2. Nucleus is an OS of the RTOS-like family. Unfortunately, closed. Mentor Graphics Rights. On sourceforge are the source code for the shaggy 2004 version of x86. Similarly, try to assemble, run in a virtual machine. Write "Hello world." (Of course, the OS version of 15 years ago will be a little: rolleyes: different, but still worth a try.)
3. Buy some IoT garbage from MediaTek, master the work with their devkit SPFlashTool and MAUI.
4. Picking any existing firmware.

Chettuser,
Hardware In China, poor soldering and flux residues on the circuit board are often found. Sometimes you watch a board from the body - it seems that it was soldered in the district palace of pioneers. It may also be a defective microphone or the radio module may spontaneously lose the network. There is only one way out - to disassemble the bodies, carefully look at the board with your eyes and dissolve all the crookedly made solders, rinse with solvent galoshes from flux residues (preferably not in the apartment). Collect back as it was.

So this is almost all Chinese button players have long been able to. Or do you need a strictly branded device?

Question to experts: how accurately does MEmu simulate real hardware? Is it possible to run firmware on it for some really existing phones? Is there a specialized emulator for launching and debugging real firmware, including non-Android push buttons? (I really would not want to install full Android Studio for this, bulky and heavy, so as not to shoot sparrows from a grenade launcher.)

Well, there was the opposite case when Matteus Rust flew to us. Muttered "ely-burns, but there every dummy knows how to fly a plane!"

Given that it was extremely low-budget with the appropriate quality of filming (flips on the fishing line are worth it, and with implausible numbers). Thought, look and forget, and the film literally flew into space - pulled a great acting game and script.
And at the same time, the first Terminator is somewhere out there. The same low-budget, so the main role is not particularly deliberate given to the then unknown Arnie Schwarzenegger. As a result, the film, originally conceived as a pop action movie with a stupid script, broke all imaginable and inconceivable rental records.

By the way, there is an interesting analysis on YouTube - look for a movie called “What does Alice Selezneva and Terminator have in common?”.

... Most likely, they just want to hyping on the idea of ​​“freedom and cleanliness of the code”, to thunder in the news, to push their start-up to expensive uncles expensive. After all, the guys are probably not idiots and understand that they are releasing a deliberately stillborn (in a commercial sense) product. It is easier for an ordinary person to buy any decent jammer and roll some Cyanogen on it, if you really need a root.

mec.Perfarator,
1. Look for the Ginzzu brand from the Chinese on Ali and other sites.
2. Sigma X-Treme PQ67 (Ukrainian brand, send to Russia - x / z)
3. Evolveo StrongPhone WiFi (discontinued, not supported)

Actually, it is called Nucleus OS. It was written back in the shaggy year by some enthusiasts, but has long gone into commerce.

Without creating your own device is impractical. And so - you can merge the existing one and pick it as much as possible. I myself soon plan to seriously dig my dialer. I think it’s quite possible to understand, first at least understand where the boot loader is, where the kernel is, and where the file system is, understand the format of the executable files (most likely there will be a banal .ELF), dig deeper into several files with the debugger. Can still find on the phone circuit board RS-232, see what goes to the port.
Browser shit in the spirit of Android 2.0, and even with closed source. Well, his shaggy grandmother.

Yes, in general, it’s clear that -to be a means of communication (not a means of communication). I read the topic. Some commentators demanding Skype and other heresies are simply surprising. You forgot the most important thing - IP / IPv6 dual stack support! And I would add:
1. The simplest packet filtering functions (firewall, if in Russian)
2. Support bluetooth HID for keyboards
3. The ability to configure DHCP for tethering and support for multiple profiles in the access point mode
4. Text editor. (It was always surprising why the ebook reader is almost everywhere, and the normal text editor is fundamentally absent.) I must understand all the encodings that are supported in glibc.
5. FTP client and simple FTP server. (For some reason, Opera mini, for some mysterious reason, does not know how to FTP).