RangePi

have you tried: "Holding down the RangePi BOTSEL button while dragging this file into the mounted RP2 folder will allow you to load it." from paragraph about firmware update from their github page? Maybe it needs to be pressed all the time during update?

The problem is that it doesn't mount any folder which makes it impossible to drag any file to it.

even when the button is pressed all the time from the moment of connecting to the USB? I don't own one so I only can guess from the manual but it seems to state that the button needs to be pressed all the time... 

Yes, I'm pressing the button all the time from unconnected to it is connected and even wait some seconds before releasing it.

Hi, 

Possibly, you may not need to perform this process, if it came pre-installed. 

If you're trying to upgrade it, be aware that the firmeware on GitHub is several years old anyway.

If, when you plug it in, you hear the short tone (or whatever sound or alert your PC usually makes) that a USB device has been plugged in, then there's a chance it is functioning and you might simply be able to proceed directly to using Thonny to access it. You won't see any Mass Storage Device in this case.

That being said, if the boot button was held down while plugging in, and then released, then the mass storage device ought to appear so that you can upgrade it. There's a chance the button could be faulty (some of the cheap ones are fragile and damage if pressed off-center). Although the instructions state to hold down the BOOT button all the time, that's unusual for a RP2040 board. There's no circuit that I could find to check. The typical method is to first hold down the button, then insert into the PC, then release the button. The 1-minute video here would apply since your board also contains an RP2040: https://www.youtube.com/watch?v=os4mv_8jWfU

Anyway, as mentioned, it may be worth just attempting to use Thonny first.

Yes I have tried using Thonny now and after re-installing it I managed to connect and use the RangePi with python. That’s nice, but I really would like to be able to re-flash the device and maybe use it with C / C++. I have been trying to follow that process when plugging it in, but still no mass storage.

Maybe worth asking the manufacturer; they may have made a mistake in the documentation, or possibly disabled the boot capability if users were accidentally pressing it when inserting it in. No idea, but the manufacturer will know for sure. The procedure for a typical RP2040 board has already been mentioned. Your board is already quite weird (strange combination, USB-A port so that it sticks out, plus a RP2040 which is technically unnecessary when a USB-UART could have been used), so who knows what other unusual things they did in the circuitry.

You could simply buy a Pi Pico board for a few $, it's cheaper, there is a lot more information on it, and the Bootloader button works on it : )

If it's the LoRa you're interested in, the LoRa module (E22-900T22S) is cheap and easy to obtain, simple to wire up and there's plenty of documentation for it.

Yes, I think so too. I have now mailed the manufacturer a question and hope they give me an answer for this. It seems that the firmware maybe have the mass storage option disabled or something as you are talking about. Maybe I'll check out other products fort this purpose.