diff --git a/README.md b/README.md
index 4fd2a53cc..47a27e30e 100644
--- a/README.md
+++ b/README.md
@@ -34,9 +34,6 @@ Then, download and build Parity:
 git clone https://github.com/ethcore/parity
 cd parity
 
-# parity should be built with rust beta
-multirust override beta
-
 # build in release mode
 cargo build --release
 ```
diff --git a/util/bigint/src/uint.rs b/util/bigint/src/uint.rs
index 3dfb9dd45..ea617d570 100644
--- a/util/bigint/src/uint.rs
+++ b/util/bigint/src/uint.rs
@@ -36,6 +36,7 @@
 //! The functions here are designed to be fast.
 //!
 
+#[cfg(all(asm_available, target_arch="x86_64"))]
 use std::mem;
 use std::fmt;
 use std::cmp;