diff --git a/tools/environments.bzl b/tools/environments.bzl
index 68e78de..c82a01b 100644
--- a/tools/environments.bzl
+++ b/tools/environments.bzl
@@ -1,5 +1,6 @@
 # Contains some helpers for working with environments.
 
 mcu_cpus = [
-  "@//tools:cortex-m4f",
+    "@//tools:cortex-m4f",
+    "@//tools:cortex-m4f-k22",
 ]