diff --git a/lib/src/lib.rs b/lib/src/lib.rs
index 2328548..dfbd22b 100644
--- a/lib/src/lib.rs
+++ b/lib/src/lib.rs
@@ -1269,9 +1269,8 @@ impl Node {
             info!(log, "image already downloaded: {path}");
             return Ok(());
         }
-        let url = format!(
-            "https://oxide-falcon-assets.s3.us-west-2.amazonaws.com/{iname}"
-        );
+        let asset_base = asset_base();
+        let url = format!("{asset_base}/{iname}");
         info!(log, "trying to download {url}");
 
         download_large_file(url.as_str(), path, log).await?;
@@ -1821,6 +1820,15 @@ pub(crate) fn dataset() -> String {
     }
 }
 
+pub(crate) fn asset_base() -> String {
+    match std::env::var("FALCON_ASSET_BASE") {
+        Ok(s) if !s.is_empty() => s,
+        _ => {
+            "https://oxide-falcon-assets.s3.us-west-2.amazonaws.com".to_string()
+        }
+    }
+}
+
 fn libnet_retry<F>(f: F) -> Result<(), Error>
 where
     F: Fn() -> Result<(), libnet::Error>,
diff --git a/lib/src/ovmf.rs b/lib/src/ovmf.rs
index a04c568..9a7862f 100644
--- a/lib/src/ovmf.rs
+++ b/lib/src/ovmf.rs
@@ -5,10 +5,13 @@ use std::fs;
 use std::io;
 use std::time::Duration;
 
-const OVMF_URL: &str =
-    "https://oxide-falcon-assets.s3.us-west-2.amazonaws.com/OVMF_CODE.fd";
-const OVMF_DIGEST_URL: &str =
-    "https://oxide-falcon-assets.s3.us-west-2.amazonaws.com/OVMF_CODE.fd.sha256.txt";
+fn ovmf_url() -> String {
+    format!("{}/OVMF_CODE.fd", crate::asset_base())
+}
+
+fn ovmf_digest_url() -> String {
+    format!("{}/OVMF_CODE.fd.sha256.txt", crate::asset_base())
+}
 
 pub(crate) async fn ensure_ovmf_fd(
     falcon_dir: &str,
@@ -31,7 +34,7 @@ pub(crate) async fn ensure_ovmf_fd(
 
 async fn download_ovmf(path: &str, log: &Logger) -> Result<()> {
     info!(log, "downloading ovmf");
-    crate::download_large_file(OVMF_URL, path, log).await?;
+    crate::download_large_file(&ovmf_url(), path, log).await?;
     Ok(())
 }
 
@@ -63,7 +66,7 @@ async fn get_expected_ovmf_digest_impl() -> Result<String> {
         .connect_timeout(Duration::from_secs(15))
         .timeout(Duration::from_secs(30))
         .build()?;
-    let response = client.get(OVMF_DIGEST_URL).send().await?;
+    let response = client.get(ovmf_digest_url()).send().await?;
     let text = response.text().await?;
     Ok(text.trim().to_owned())
 }