diff --git a/boot/zephyr/CMakeLists.txt b/boot/zephyr/CMakeLists.txt
index 5bc32ac..6cdb024 100644
--- a/boot/zephyr/CMakeLists.txt
+++ b/boot/zephyr/CMakeLists.txt
@@ -62,7 +62,7 @@
 set(NRF_DIR "${MCUBOOT_DIR}/ext/nrf")
 
 if(CONFIG_BOOT_USE_NRF_CC310_BL)
-set(NRFXLIB_DIR $ENV{ZEPHYR_BASE}/../nrfxlib)
+set(NRFXLIB_DIR ${ZEPHYR_BASE}/../nrfxlib)
 assert_exists(NRFXLIB_DIR)
 # Don't include this if we are using west
  add_subdirectory(${NRFXLIB_DIR} ${PROJECT_BINARY_DIR}/nrfxlib)