Upload failed with nRF52840 on Ubuntu Linux 18.04 [FIX]

Wireless & IoT Bluetooth
1

Compile OK but upload failed. Adafruit nRF52840 works fine on the same computer. The problem is the Linux Modem Manager opens /dev/ttyACMx ports after a port reset which prevents the DFU loader from opening the port. One solution is to “sudo apt remove modemmanager”. Or add a udev rule so modem manager ignores SparkFun boards. This is why the Adafruit board works because I added /etc/udev/rules.d/99-adafruit-boards.txt a long time ago.

I created /etc/udev/rules.d/99-sparkfun-udev.rules which contains the following. This fixes the problem without removing Modem Manager.

# Rule to blacklist SparkFun USB boards from being manipulated by ModemManager.
# Fixes issue with hanging references to /dev/ttyACM* devices
ATTRS{idVendor}=="1b4f", ENV{ID_MM_DEVICE_IGNORE}="1"
2

Hi bbx10node,

Thanks for sharing this fix! I have edited the title to include [FIX] just to make it clear that this is a solution so it is easier to search for if other users run into the same problem.

Thanks again and Happy Hacking!

3

Wow! I’ve been struggling for months with both the Adafruit and Sparkfun NRF52 boards and /dev/ttyACMx flakiness. Now, it just works.