(in Vagrant)

1. Delete any contents in your /vagrant/ext/ncs directory
2. $ cd /vagrant/ext/ncs
3. $ west init -m https://github.com/jlwatson/sdk-nrf
4. $ west update
5. $ west zephyr-export
6. Install the zephyr dependencies (just to make sure)

pip3 install -r zephyr/scripts/requirements.txt
pip3 install -r nrf/scripts/requirements.txt
pip3 install -r bootloader/mcuboot/scripts/requirements.txt

7. Update your ~/.bashrc with:

export ZEPHYR_BASE=/vagrant/ext/ncs/zephyr
source $(ZEPHYR_BASE)/zephyr-env.sh

8. Ensure that your app Makefile sets BOARD = nrf9160 and run make clean before building.