diff --git a/hermit/build.rs b/hermit/build.rs
index 4d3ba257c..ceebb46cd 100644
--- a/hermit/build.rs
+++ b/hermit/build.rs
@@ -162,6 +162,8 @@ impl KernelSrc {
 		// HERMIT_LOG_LEVEL_FILTER sets the log level filter at compile time
 		println!("cargo:rerun-if-env-changed=HERMIT_LOG_LEVEL_FILTER");
 		println!("cargo:rerun-if-env-changed=HERMIT_CAREFUL");
+		println!("cargo:rerun-if-env-changed=HERMIT_MTU");
+		println!("cargo:rerun-if-env-changed=HERMIT_MRG_RXBUF_SIZE");
 		println!("cargo:rerun-if-env-changed=NO_COLOR");
 	}