diff --git a/boot/zephyr/CMakeLists.txt b/boot/zephyr/CMakeLists.txt
index 6050e0d..470103c 100644
--- a/boot/zephyr/CMakeLists.txt
+++ b/boot/zephyr/CMakeLists.txt
@@ -52,7 +52,7 @@
 macro(app_set_runner_args)
   if(CONFIG_ZEPHYR_TRY_MASS_ERASE)
     board_runner_args(dfu-util "--dfuse-modifiers=force:mass-erase")
-    board_runner_args(pyocd "--flashtool-opt=-ce")
+    board_runner_args(pyocd "--flash-opt=-e=chip")
     board_runner_args(nrfjprog "--erase")
   endif()
 endmacro()