diff --git a/artiq/firmware/libksupport/lib.rs b/artiq/firmware/libksupport/lib.rs
index 76c8c420d..04c9977e6 100644
--- a/artiq/firmware/libksupport/lib.rs
+++ b/artiq/firmware/libksupport/lib.rs
@@ -1,7 +1,5 @@
-#![feature(lang_items, needs_panic_runtime, asm, libc, stmt_expr_attributes)]
-
+#![feature(lang_items, asm, libc)]
 #![no_std]
-#![needs_panic_runtime]
 
 extern crate alloc_none;
 #[macro_use]
diff --git a/artiq/firmware/runtime/lib.rs b/artiq/firmware/runtime/lib.rs
index 0fb41da5a..0eaeb6a95 100644
--- a/artiq/firmware/runtime/lib.rs
+++ b/artiq/firmware/runtime/lib.rs
@@ -1,5 +1,5 @@
 #![no_std]
-#![feature(libc, const_fn, stmt_expr_attributes, repr_simd, asm, lang_items)]
+#![feature(libc, const_fn, repr_simd, asm, lang_items)]
 
 extern crate alloc_artiq;
 #[macro_use]