diff --git a/artiq/firmware/libboard/i2c.rs b/artiq/firmware/libboard/i2c.rs
index ef4f36051..6f3880645 100644
--- a/artiq/firmware/libboard/i2c.rs
+++ b/artiq/firmware/libboard/i2c.rs
@@ -1,3 +1,4 @@
+#[cfg(has_i2c)]
 use csr;
 
 #[cfg(has_i2c)]