diff --git a/build b/build
index 1dc2c05..feceda4 100755
--- a/build
+++ b/build
@@ -1,10 +1,11 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 RUST_TOOLCHAIN="nightly"
 
 set +e
 git submodule update --init --recursive
 pushd wallet-wasm
+rustup toolchain install ${RUST_TOOLCHAIN} && \
 rustup target add --toolchain ${RUST_TOOLCHAIN} wasm32-unknown-unknown && \
 cargo  +${RUST_TOOLCHAIN} build --target wasm32-unknown-unknown --release --verbose && \
 popd && \