diff --git a/crates/engine/src/io.rs b/crates/engine/src/io.rs
index 8c774d83..464740e5 100644
--- a/crates/engine/src/io.rs
+++ b/crates/engine/src/io.rs
@@ -578,7 +578,7 @@ pub const BUNDLE_EXTENSION: &str = "scraftz";
 
 /// Most entries and bytes a bundle may unpack to (bundles are hostile input).
 const MAX_BUNDLE_ENTRIES: usize = 10_000;
-const MAX_BUNDLE_BYTES: u64 = 4 << 30;
+const MAX_BUNDLE_BYTES: u64 = 1 << 30;
 
 /// Hands a finished file (name, bytes) to the person on a host without a filesystem: the web app
 /// installs one that starts a download. Native builds write files and never install it.