diff --git a/misc/android/README b/misc/android/README
index f01ca2cc2b657a..38e7cf41e3c014 100644
--- a/misc/android/README
+++ b/misc/android/README
@@ -6,18 +6,18 @@ mobile subrepository:
 
 	https://github.com/golang/mobile
 
-To run the standard library tests, see androidtest.bash. Run it as
+To run the standard library tests, enable Cgo and use an appropriate
+C compiler from the Android NDK. For example,
 
-	CC_FOR_TARGET=$STANDALONE_NDK_PATH/bin/clang GOARCH=arm64 ./androidtest.bash
-
-To create a standalone android NDK tool chain, follow the instructions on
-
-	https://developer.android.com/ndk/guides/standalone_toolchain
+	CGO_ENABLED=1 \
+	GOOS=android \
+	GOARCH=arm64 \
+	CC=$NDK/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android21-clang \
+	./all.bash
 
 To run tests on the Android device, add the bin directory to PATH so the
 go tool can find the go_android_$GOARCH_exec wrapper generated by
-androidtest.bash. Then, use the same GOARCH as when androidtest.bash ran
-and set GOOS to android. For example, to run the go1 benchmarks
+make.bash. For example, to run the go1 benchmarks
 
 	export PATH=$GOROOT/bin:$PATH
 	cd $GOROOT/test/bench/go1/
diff --git a/misc/android/cleaner.go b/misc/android/cleaner.go
deleted file mode 100644
index edbbdcd0ef2869..00000000000000
--- a/misc/android/cleaner.go
+++ /dev/null
@@ -1,41 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build ignore
-
-// Cleaner removes anything from /data/local/tmp/goroot not on a builtin list.
-// Used by androidtest.bash.
-package main
-
-import (
-	"log"
-	"os"
-	"path/filepath"
-	"strings"
-)
-
-func main() {
-	const goroot = "/data/local/tmp/goroot"
-	expect := make(map[string]bool)
-	for _, f := range strings.Split(files, "\n") {
-		expect[filepath.Join(goroot, f)] = true
-	}
-
-	err := filepath.Walk(goroot, func(path string, info os.FileInfo, err error) error {
-		if expect[path] {
-			return nil
-		}
-		log.Printf("removing %s", path)
-		if err := os.RemoveAll(path); err != nil {
-			return err
-		}
-		if info.IsDir() {
-			return filepath.SkipDir
-		}
-		return nil
-	})
-	if err != nil {
-		log.Fatal(err)
-	}
-}
diff --git a/misc/android/go_android_exec.go b/misc/android/go_android_exec.go
index e36edacc76b938..1a8ae7070e38fb 100644
--- a/misc/android/go_android_exec.go
+++ b/misc/android/go_android_exec.go
@@ -13,6 +13,7 @@ import (
 	"fmt"
 	"go/build"
 	"io"
+	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -78,6 +79,8 @@ func main() {
 	deviceCwd := filepath.Join(deviceGoroot, subdir)
 	if !inGoRoot {
 		deviceCwd = filepath.Join(deviceGopath, subdir)
+	} else {
+		adbSyncGoroot()
 	}
 
 	// Binary names can conflict.
@@ -164,3 +167,46 @@ func subdir() (pkgpath string, underGoRoot bool) {
 		cwd, runtime.GOROOT(), build.Default.GOPATH)
 	return "", false
 }
+
+// adbSyncGoroot ensures that files necessary for testing the Go standard
+// packages are present on the attached device.
+func adbSyncGoroot() {
+	// Also known by cmd/dist. The bootstrap command deletes the file.
+	statPath := filepath.Join(os.TempDir(), "go_android_exec-adb-sync-status")
+	stat, err := os.OpenFile(statPath, os.O_CREATE|os.O_RDWR, 0666)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer stat.Close()
+	// Serialize check and syncing.
+	if err := syscall.Flock(int(stat.Fd()), syscall.LOCK_EX); err != nil {
+		log.Fatal(err)
+	}
+	s, err := ioutil.ReadAll(stat)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if string(s) == "done" {
+		return
+	}
+	devRoot := "/data/local/tmp/goroot"
+	run("shell", "rm", "-rf", devRoot)
+	run("shell", "mkdir", "-p", devRoot+"/pkg")
+	goroot := runtime.GOROOT()
+	goCmd := filepath.Join(goroot, "bin", "go")
+	runtimea, err := exec.Command(goCmd, "list", "-f", "{{.Target}}", "runtime").Output()
+	if err != nil {
+		log.Fatal(err)
+	}
+	pkgdir := filepath.Dir(string(runtimea))
+	if pkgdir == "" {
+		log.Fatal("could not find android pkg dir")
+	}
+	for _, dir := range []string{"src", "test", "lib"} {
+		run("push", filepath.Join(goroot, dir), filepath.Join(devRoot))
+	}
+	run("push", filepath.Join(pkgdir), filepath.Join(devRoot, "pkg/"))
+	if _, err := stat.Write([]byte("done")); err != nil {
+		log.Fatal(err)
+	}
+}
diff --git a/src/androidtest.bash b/src/androidtest.bash
index 12f240cc5807e5..ba776d22780f74 100755
--- a/src/androidtest.bash
+++ b/src/androidtest.bash
@@ -4,8 +4,6 @@
 # license that can be found in the LICENSE file.
 
 # For testing Android.
-# The compiler runs locally, then a copy of the GOROOT is pushed to a
-# target device using adb, and the tests are run there.
 
 set -e
 ulimit -c 0 # no core files
@@ -31,55 +29,9 @@ fi
 export CGO_ENABLED=1
 unset GOBIN
 
-# Do the build first, so we can build the 'cleaner' binary.
-# Also lets us fail early before the (slow) adb push if the build is broken.
-. ./make.bash --no-banner
 export GOROOT=$(dirname $(pwd))
+# Put the exec wrapper into PATH
 export PATH=$GOROOT/bin:$PATH
 
-export pkgdir=$(dirname $(go list -f '{{.Target}}' runtime))
-if [ "$pkgdir" = "" ]; then
-	echo "could not find android pkg dir" 1>&2
-	exit 1
-fi
-
-export ANDROID_TEST_DIR=/tmp/androidtest-$$
-
-function cleanup() {
-	rm -rf ${ANDROID_TEST_DIR}
-}
-trap cleanup EXIT
-
-# Push GOROOT to target device.
-#
-# The adb sync command will sync either the /system or /data
-# directories of an android device from a similar directory
-# on the host. We copy the files required for running tests under
-# /data/local/tmp/goroot. The adb sync command does not follow
-# symlinks so we have to copy.
-export ANDROID_PRODUCT_OUT="${ANDROID_TEST_DIR}/out"
-FAKE_GOROOT=$ANDROID_PRODUCT_OUT/data/local/tmp/goroot
-mkdir -p $FAKE_GOROOT
-mkdir -p $FAKE_GOROOT/pkg
-cp -a "${GOROOT}/src" "${FAKE_GOROOT}/"
-cp -a "${GOROOT}/test" "${FAKE_GOROOT}/"
-cp -a "${GOROOT}/lib" "${FAKE_GOROOT}/"
-cp -a "${pkgdir}" "${FAKE_GOROOT}/pkg/"
-
-echo '# Syncing test files to android device'
-adb $GOANDROID_ADB_FLAGS shell mkdir -p /data/local/tmp/goroot
-time adb $GOANDROID_ADB_FLAGS sync data &> /dev/null
-
-export CLEANER=${ANDROID_TEST_DIR}/androidcleaner-$$
-cp ../misc/android/cleaner.go $CLEANER.go
-echo 'var files = `' >> $CLEANER.go
-(cd $ANDROID_PRODUCT_OUT/data/local/tmp/goroot; find . >> $CLEANER.go)
-echo '`' >> $CLEANER.go
-go build -o $CLEANER $CLEANER.go
-adb $GOANDROID_ADB_FLAGS push $CLEANER /data/local/tmp/cleaner
-adb $GOANDROID_ADB_FLAGS shell /data/local/tmp/cleaner
-
-echo ''
-
 # Run standard tests.
-bash run.bash --no-rebuild
+bash all.bash
diff --git a/src/cmd/dist/build.go b/src/cmd/dist/build.go
index 6388e3e8632872..43e1fe66f3b73f 100644
--- a/src/cmd/dist/build.go
+++ b/src/cmd/dist/build.go
@@ -1366,7 +1366,11 @@ func cmdbootstrap() {
 	// Remove go_bootstrap now that we're done.
 	xremove(pathf("%s/go_bootstrap", tooldir))
 
-	// Build the exec wrapper if necessary.
+	if goos == "android" {
+		// Make sure the exec wrapper will sync a fresh $GOROOT to the device.
+		xremove(pathf("%s/go_android_exec-adb-sync-status", os.TempDir()))
+	}
+
 	if wrapperPath := wrapperPathFor(goos, goarch); wrapperPath != "" {
 		oldcc := os.Getenv("CC")
 		os.Setenv("GOOS", gohostos)