Can't flash XIAO nrf52840

[Oli]

I'm trying to flash a XIAO nrf52840 following the instructions for flashing with UF2 but it won't seem to work. After I drag and drop the zephyr.uf2 file in the mounted drive, I get the following error message:

"The Finder can't complete the operation because some data in "zephyr.uf2" can't be read or written. (Error code -36)".

I tested both with the blinky sample application and my own custom application.

I also tested with two different XIAO nrf52840 boards with the same error message.

[Simonr]

Hi

Did you do the correct steps to put the XIAO into bootloader mode? "double tap the reset button to the left of the USB connector". We're not using UF2 flashing a lot, but I found this page on the Adafruit blog regarding UF2 on Mac: https://blog.adafruit.com/2022/10/31/uploading-uf2-files-with-macos-13-0-ventura-apple-microbit_edu-raspberry_pi-circuitpython/ 

Also from this post it says "If you're using MakeCode on a Mac, you need to make sure to upload the bootloader to avoid a serious problem with newer versions of MacOS. See instructions and more details here."

I tried to look around for an explanation on error code -36 but couldn't find anything, so I suggest you reach out to Adafruit support if you're not able to get the device flashing with UF2. Our suggestion would be to get a J-Link debugger or nRF52 series DK to use as a debugger/flashing device on your end as that's better for actual development. The UF2 bootloader is better for just flashing AFAIK.

Best regards,

Simon