diff --git a/ci/docker/mipsel-unknown-linux-musl/Dockerfile b/ci/docker/mipsel-unknown-linux-musl/Dockerfile
index 7488662ef2..5d19d7c93d 100644
--- a/ci/docker/mipsel-unknown-linux-musl/Dockerfile
+++ b/ci/docker/mipsel-unknown-linux-musl/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:18.10
+FROM ubuntu:18.04
 
 RUN apt-get update && \
     apt-get install -y --no-install-recommends \
diff --git a/crates/stdarch-test/src/wasm.rs b/crates/stdarch-test/src/wasm.rs
index fc4ced6282..612ff10d90 100644
--- a/crates/stdarch-test/src/wasm.rs
+++ b/crates/stdarch-test/src/wasm.rs
@@ -32,8 +32,8 @@ pub(crate) fn disassemble_myself() -> HashSet<Function> {
     // "wasm-bindgen-test_bg". When running in node this is actually a shim JS
     // file. Ask node where that JS file is, and then we use that with a wasm
     // extension to find the wasm file itself.
-    let js_shim = resolve("wasm-bindgen-test_bg");
-    let js_shim = Path::new(&js_shim).with_extension("wasm");
+    let js_shim = resolve("wasm-bindgen-test");
+    let js_shim = Path::new(&js_shim).with_file_name("wasm-bindgen-test_bg.wasm");
 
     // Execute `wasm2wat` synchronously, waiting for and capturing all of its
     // output. Note that we pass in a custom `maxBuffer` parameter because we're