diff --git a/app_state.py b/app_state.py
index 22a179f..73a0140 100644
--- a/app_state.py
+++ b/app_state.py
@@ -8,7 +8,7 @@ so later rebinding would only ever be seen by the module that did it.
 import configparser
 import os
 
-VERSION = "0.0.0.137"
+VERSION = "0.0.0.138"
 PROPERTIES_FILE = os.path.join(os.path.dirname(os.path.abspath(__file__)), "editor.properties")
 DEFAULT_GRID_SIZE = 10
 DEFAULT_ADD_TIMESTAMP = True
diff --git a/device_session.py b/device_session.py
index adcd48b..6995481 100644
--- a/device_session.py
+++ b/device_session.py
@@ -176,6 +176,41 @@ class DeviceSession:
                 for cid in parent.children
                 if self.sox_client.cache_get(cid) is not None]
 
+    def used_kit_names(self):
+        """Every kit a component on the device belongs to, loading the whole tree to see.
+
+        The DOM only holds what has been opened, so it cannot answer this on its own. Only
+        the tree is read — no config or runtime.
+
+        Requests go one at a time. A small controller handles a single folder's burst fine,
+        but a back-to-back stream of them fills its receive buffer; it stops acking, and
+        DASP closes the whole session ("unacked send timeout"). Waiting for each reply
+        before sending the next keeps it at the pace the device sets. Anything already
+        cached costs nothing, so only the first call is slow.
+        """
+        client = self.sox_client
+        if client is None:
+            return set()
+
+        pending = [0]
+        loaded = 0
+        while pending:
+            comp_id = pending.pop()
+            comp = client.cache_get(comp_id)
+            if comp is None:
+                comp = client.load_ids([comp_id], checked=False)[0]
+                loaded += 1
+                if loaded % 20 == 0:
+                    app_state.set_status(f"Reading components from the device… {loaded}")
+                    if app_state.status_label is not None:
+                        app_state.status_label.update_idletasks()
+            if comp is not None:
+                pending.extend(comp.children)
+
+        parts = client.schema_parts or []
+        return {parts[c.kit_id].name for c in client.cache
+                if c is not None and 0 <= c.kit_id < len(parts)}
+
     def find_component_of_type(self, type_name, slot_name):
         """A component of `type_name` with `slot_name` read, loading where services live.
 
@@ -294,8 +329,10 @@ class DeviceSession:
         schema_elem = ET.SubElement(sax_root, "schema")
         if self.sox_client and self.sox_client.schema_parts:
             for part in self.sox_client.schema_parts:
+                # Sox sends the checksum as a signed int; .sax files and manifest names
+                # spell it as 8 hex digits, and nothing matches unless this does too.
                 ET.SubElement(schema_elem, "kit",
-                              name=part.name, checksum=str(part.checksum))
+                              name=part.name, checksum=f"{part.checksum & 0xFFFFFFFF:08x}")
 
         app_elem = ET.SubElement(sax_root, "app")
         if root_comp is not None:
diff --git a/manage_kits.py b/manage_kits.py
index 6b0c642..e78a487 100644
--- a/manage_kits.py
+++ b/manage_kits.py
@@ -82,6 +82,11 @@ def column_label(version, checksum):
     return version if version else checksum
 
 
+def same_checksum(a, b):
+    """Whether two checksums name the same build, whatever their zero-padding."""
+    return bool(a) and bool(b) and a.lower().lstrip("0") == b.lower().lstrip("0")
+
+
 def action_options(kit_name, current_checksum, is_declared, builds):
     """The Action dropdown for one kit: (label, checksum to apply) pairs, no-op first.
 
@@ -91,7 +96,7 @@ def action_options(kit_name, current_checksum, is_declared, builds):
     """
     installed_version = None
     for version, checksum in builds:
-        if checksum == current_checksum:
+        if same_checksum(checksum, current_checksum):
             installed_version = version
             break
 
@@ -109,7 +114,7 @@ def action_options(kit_name, current_checksum, is_declared, builds):
     installed_rank = palette.version_sort_key(installed_version) if installed_version else None
 
     for version, checksum in builds:
-        if is_declared and checksum == current_checksum:
+        if is_declared and same_checksum(checksum, current_checksum):
             continue
 
         label = build_label(version, checksum)
@@ -176,7 +181,7 @@ def collect_rows():
                 installed_text = NO_CHECKSUM
             else:
                 installed_text = column_label(
-                    next((v for v, c in builds if c == checksum), ""), checksum
+                    next((v for v, c in builds if same_checksum(c, checksum)), ""), checksum
                 )
 
             rows.append({
@@ -512,7 +517,7 @@ class KitsPanel:
             if "section" in row or not row["declared"] or not row["latest"]:
                 continue
             latest_checksum = row["latest"][1]
-            if latest_checksum != row["checksum"]:
+            if not same_checksum(latest_checksum, row["checksum"]):
                 selections.append((row["kit"], latest_checksum))
 
         if selections:
diff --git a/sax_file.py b/sax_file.py
index d53cecd..86b22e8 100644
--- a/sax_file.py
+++ b/sax_file.py
@@ -501,6 +501,18 @@ def used_kit_names():
     if app_state.xml_root_element is None:
         return names
 
+    # A device session's DOM only holds the folders opened so far.
+    session = app_state.device_session
+    if session is not None and session.is_connected:
+        try:
+            return session.used_kit_names()
+        except Exception as error:
+            messagebox.showwarning(
+                "Kits",
+                f"Could not read every component from the device:\n{error}\n\n"
+                "Kits shown as used come only from the folders opened so far.",
+            )
+
     for comp in app_state.xml_root_element.iter("comp"):
         type_str = comp.get("type") or ""
         if "::" in type_str: