diff --git a/zephyr/Makefile.zephyr b/zephyr/Makefile.zephyr
index 52904ff8d..ad905a4db 100644
--- a/zephyr/Makefile.zephyr
+++ b/zephyr/Makefile.zephyr
@@ -14,10 +14,11 @@
 # limitations under the License.
 #
 
-KERNEL_TYPE = nano
+KERNEL_TYPE = micro
 # BOARD must be passed on command line from main Makefile
 #BOARD =
 CONF_FILE = prj.conf
+MDEF_FILE = prj.mdef
 
 #export SOURCE_DIR = $(ZEPHYR_BASE)/samples/static_lib/hello_world
 export LDFLAGS_zephyr += -L$(CURDIR)
diff --git a/zephyr/prj.mdef b/zephyr/prj.mdef
new file mode 100644
index 000000000..5a7312f89
--- /dev/null
+++ b/zephyr/prj.mdef
@@ -0,0 +1,5 @@
+% Application       : MicroPython
+
+% TASK NAME  PRIO ENTRY STACK GROUPS
+% ==================================
+  TASK MAIN  7    main  4096 [EXE]