diff --git a/.travis.yml b/.travis.yml
index 6c4fd55..39ddb5d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,6 @@
 language: go
 go:
 - 1.11.1
-env:
-- GO111MODULE=on
 install:
 - ./script/bootstrap
 script:
diff --git a/script/bootstrap b/script/bootstrap
index dd48814..78b4a25 100755
--- a/script/bootstrap
+++ b/script/bootstrap
@@ -1,7 +1,9 @@
 #!/bin/bash -ex
 
-# Install go module dependencies.
-go mod download
+# Limit dependencies to golang.org/x repos
+go get -u \
+    golang.org/x/arch/x86/... \
+    golang.org/x/tools/go/...
 
 # Install golangci-lint
 golangci_lint_version='v1.12.3'