diff --git a/core/archipelago/src/api/rpc/package/async_lifecycle.rs b/core/archipelago/src/api/rpc/package/async_lifecycle.rs
index 3c99a163..ada96e83 100644
--- a/core/archipelago/src/api/rpc/package/async_lifecycle.rs
+++ b/core/archipelago/src/api/rpc/package/async_lifecycle.rs
@@ -295,6 +295,12 @@ impl RpcHandler {
             .ok_or_else(|| anyhow::anyhow!("Missing package id"))?
             .to_string();
         super::validation::validate_app_id(&package_id)?;
+        // Update is stop → pull → remove → recreate, i.e. a fresh start by
+        // another name: on a disk that shrank since install it would resume
+        // cuprate's unprunable sync unchecked. Same gate as install and
+        // start, run BEFORE the Updating flip so a refusal leaves the app
+        // cleanly in its previous state.
+        super::dependencies::check_cuprate_disk_compatibility(&package_id).await?;
 
         // Reject if already in a transitional lifecycle.
         {
diff --git a/core/archipelago/src/api/rpc/package/runtime.rs b/core/archipelago/src/api/rpc/package/runtime.rs
index 8e0c02a1..de627004 100644
--- a/core/archipelago/src/api/rpc/package/runtime.rs
+++ b/core/archipelago/src/api/rpc/package/runtime.rs
@@ -257,6 +257,11 @@ impl RpcHandler {
             .and_then(|v| v.as_str())
             .ok_or_else(|| anyhow::anyhow!("Missing package id"))?;
         validate_app_id(package_id)?;
+        // Restart is stop + recreate, so on a disk that shrank below the cuprate
+        // minimum after install it resumes the doomed unprunable sync just like
+        // start would — same gate, same "fail before clearing user-stopped /
+        // flipping state" contract (see handle_package_start).
+        super::dependencies::check_cuprate_disk_compatibility(package_id).await?;
 
         let single_orchestrator_app =
             self.orchestrator.is_some() && uses_single_orchestrator_app(package_id);