Clone [nrfxlib](https://github.com/NordicPlayground/nrfxlib) next to the mcuboot root folder. So that it's located `../nrfxlib` from mcuboots root folder.
## Building
make sure `root-ec-p256.pem` is set as the certificate and that `CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256` is selected not `CONFIG_BOOT_SIGNATURE_TYPE_RSA` in `prj.conf` of `boot/zephyr`.
Since it defaults to tinycrypt you'll have to go into `menuconfig` and change the implementation selection to `cc310` or also set this in `prj.conf`.