Is there any kit for Bluetooth devices that can be used to easily change factory implemented names of devices like speakers, headset etc ?
I found some tutorials, like this one here that basically shows, that it is technically possible. There was one answer on quora recommending development kit from Nordic to do it. But I assume that without soldering and stuff it wouldn't be possible and it is not as easy as flashing some firmware via usb cable connected to some device.
So is there any easy way of changing those funky factory implemented names with some regular and easily accessible kit and software? I'm just curious but if there was an easy way for doing it, I'd definitely give it a try.
Not really. Basically, the Bluetooth standard defines the communication protocol and little else. The device name, etc, will depend upon the device's implementation. The manufacturer may use an off-the-shelf Bluetooth module or develop their own and there is no prescriptive standard for how they must be programmed.
Some devices may be super easy to configure with an app or software intended to configure them. Others might require cutting traces on a PCB to isolate the Bluetooth module from the serial bus controller to overwrite its ROM before repairing it. Others might have a simple programming interface that one can either solder headers to or plug into with the right connector. And there are a huge number of other possibilities.
Basically, the closest thing to a universal programmer would be something like a Bus Pirate, not a piece of software.
If it's anything like the USB protocol (which I've been working with recently) the names are probably baked into the binary. You're likely out of luck unless you can somehow flash modified firmware.
Perhaps there's a way to give devices an alias on your machine?
I do not believe there is any way to change it without connecting directly to the device's circuitry, and in some widgets it may even be stored in the ROM, so a Flipper Zero would not be of much help (unless the board has some sort of programming interface you could connect to the Flipper Zero).