Like if you have an nRF52840: Nordic USB dongle, Arduino Nano 33 BLE, Adafruit, Sparkfun, April, Makerdairy, Fanstel, Particle or any other

[hpssjellis]

@manuelbl

Do you know what the origin of the Arduino bootloader is? I can’t find the source code online. Is it proprietary software by Nordic Semiconductor or u-blox (as the nRF52840 is part of a u-blox module)?

I do not know. Until you mentioned it, I kind of thought bootloaders, like windows drivers were magically formed. I did find this link for the Adafruit nrf52 bootloader GitHub - adafruit/Adafruit_nRF52_Bootloader: USB-enabled bootloaders for the nRF52 BLE SoC chips

Which is kind of a cool python drag and drop your code to a usb folder program installation bootloader, not really my interest area but looks like this can be put on the Nordic Dongle so I will look into it.

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As far as the Arduino Nano 33 BLE bootloader this issue seems to address if it is closed or open source Bootloader source code · Issue #23 · arduino/ArduinoCore-nRF528x-mbedos · GitHub

leaving the issues area will get to the main github.