diff --git a/apkdmverity/src/main.rs b/apkdmverity/src/main.rs
index 16490b6..b240c85 100644
--- a/apkdmverity/src/main.rs
+++ b/apkdmverity/src/main.rs
@@ -355,11 +355,17 @@
         let apk = include_bytes!("../testdata/test.apk");
         let idsig = include_bytes!("../testdata/test.apk.idsig");
         let roothash = V4Signature::from(Cursor::new(&idsig)).unwrap().hashing_info.raw_root_hash;
-        run_test_with_hash(apk.as_ref(), idsig.as_ref(), "correct", Some(&roothash), |ctx| {
-            let verity = fs::read(&ctx.result.mapper_device).unwrap();
-            let original = fs::read(&ctx.result.data_device).unwrap();
-            assert_eq!(verity.len(), original.len()); // fail fast
-            assert_eq!(verity.as_slice(), original.as_slice());
-        });
+        run_test_with_hash(
+            apk.as_ref(),
+            idsig.as_ref(),
+            "correct_custom_roothash",
+            Some(&roothash),
+            |ctx| {
+                let verity = fs::read(&ctx.result.mapper_device).unwrap();
+                let original = fs::read(&ctx.result.data_device).unwrap();
+                assert_eq!(verity.len(), original.len()); // fail fast
+                assert_eq!(verity.as_slice(), original.as_slice());
+            },
+        );
     }
 }
diff --git a/microdroid_manager/src/ioutil.rs b/microdroid_manager/src/ioutil.rs
index ab82e05..8ab2413 100644
--- a/microdroid_manager/src/ioutil.rs
+++ b/microdroid_manager/src/ioutil.rs
@@ -15,6 +15,8 @@
 //! IO utilities
 
 use anyhow::{anyhow, Result};
+use log::debug;
+use std::fmt::Debug;
 use std::fs::File;
 use std::io;
 use std::path::Path;
@@ -24,7 +26,8 @@
 const SLEEP_DURATION: Duration = Duration::from_millis(5);
 
 /// waits for a file with a timeout and returns it
-pub fn wait_for_file<P: AsRef<Path>>(path: P, timeout: Duration) -> Result<File> {
+pub fn wait_for_file<P: AsRef<Path> + Debug>(path: P, timeout: Duration) -> Result<File> {
+    debug!("waiting for {:?}...", path);
     let begin = Instant::now();
     loop {
         match File::open(&path) {
diff --git a/microdroid_manager/src/main.rs b/microdroid_manager/src/main.rs
index 4953a4c..9c1792d 100644
--- a/microdroid_manager/src/main.rs
+++ b/microdroid_manager/src/main.rs
@@ -88,13 +88,20 @@
     Ok(ret)
 }
 
-fn main() -> Result<()> {
+fn main() {
+    if let Err(e) = try_main() {
+        error!("failed with {}", e);
+        std::process::exit(1);
+    }
+}
+
+fn try_main() -> Result<()> {
     kernlog::init()?;
     info!("started.");
 
-    let metadata = load_metadata()?;
+    let metadata = load_metadata().context("Failed to load payload metadata")?;
 
-    let mut instance = InstanceDisk::new()?;
+    let mut instance = InstanceDisk::new().context("Failed to load instance.img")?;
     let saved_data = instance.read_microdroid_data().context("Failed to read identity data")?;
 
     // Verify the payload before using it.
diff --git a/tests/hostside/helper/java/android/virt/test/VirtualizationTestCaseBase.java b/tests/hostside/helper/java/android/virt/test/VirtualizationTestCaseBase.java
index 97cd426..4c8f5eb 100644
--- a/tests/hostside/helper/java/android/virt/test/VirtualizationTestCaseBase.java
+++ b/tests/hostside/helper/java/android/virt/test/VirtualizationTestCaseBase.java
@@ -61,6 +61,9 @@
 
         // disconnect from microdroid
         tryRunOnHost("adb", "disconnect", MICRODROID_SERIAL);
+
+        // remove any leftover files under test root
+        android.tryRun("rm", "-rf", TEST_ROOT + "*");
     }
 
     public static void cleanUpVirtualizationTestSetup(ITestDevice androidDevice)