diff --git a/electron/main/backend/update-center/index.ts b/electron/main/backend/update-center/index.ts
index c0eb19c9..808dd7d9 100644
--- a/electron/main/backend/update-center/index.ts
+++ b/electron/main/backend/update-center/index.ts
@@ -52,7 +52,10 @@ const categoryCache = new Map<string, Promise<StoreAppMetadataMap>>();
 
 const APTSS_LIST_UPGRADABLE_COMMAND = {
   command: "bash",
-  args: ["-lc", "env LANGUAGE=en_US aptss list --upgradable"],
+  args: [
+    "-lc",
+    "env LANGUAGE=en_US /usr/bin/apt -c /opt/durapps/spark-store/bin/apt-fast-conf/aptss-apt.conf list --upgradable -o Dir::Etc::sourcelist=/opt/durapps/spark-store/bin/apt-fast-conf/sources.list.d/aptss.list -o Dir::Etc::sourceparts=/dev/null -o APT::Get::List-Cleanup=0 | awk 'NR>1'",
+  ],
 };
 
 const DPKG_QUERY_INSTALLED_COMMAND = {
@@ -363,9 +366,10 @@ const isCommandAvailable = async (
 };
 
 export const loadUpdateCenterItems = async (
-  runCommand: UpdateCenterCommandRunner = runCommandCapture,
   storeFilter: StoreFilter = "both",
+  runCommand: UpdateCenterCommandRunner = runCommandCapture,
 ): Promise<UpdateCenterLoadItemsResult> => {
+  console.log(`[UpdateCenter] loadUpdateCenterItems called with storeFilter=${storeFilter}`);
   const [sparkEnabled, apmEnabled] = await Promise.all([
     isSourceEnabled(storeFilter, "spark")
       ? isCommandAvailable(runCommand, "aptss")
@@ -374,6 +378,7 @@ export const loadUpdateCenterItems = async (
       ? isCommandAvailable(runCommand, "apm")
       : Promise.resolve(false),
   ]);
+  console.log(`[UpdateCenter] sparkEnabled=${sparkEnabled}, apmEnabled=${apmEnabled}`);
 
   const [aptssResult, apmResult, aptssInstalledResult, apmInstalledResult] =
     await Promise.all([
@@ -397,6 +402,11 @@ export const loadUpdateCenterItems = async (
         : Promise.resolve({ code: 0, stdout: "", stderr: "" }),
     ]);
 
+  console.log(`[UpdateCenter] aptssResult: code=${aptssResult.code}, stdout=${aptssResult.stdout.substring(0, 500)}, stderr=${aptssResult.stderr.substring(0, 500)}`);
+  console.log(`[UpdateCenter] apmResult: code=${apmResult.code}, stdout=${apmResult.stdout.substring(0, 500)}, stderr=${apmResult.stderr.substring(0, 500)}`);
+  console.log(`[UpdateCenter] aptssInstalledResult: code=${aptssInstalledResult.code}, stdout=${aptssInstalledResult.stdout.substring(0, 500)}`);
+  console.log(`[UpdateCenter] apmInstalledResult: code=${apmInstalledResult.code}, stdout=${apmInstalledResult.stdout.substring(0, 500)}`);
+
   const aptssAvailable =
     sparkEnabled && (aptssResult.code === 0 || aptssInstalledResult.code === 0);
 
@@ -421,6 +431,8 @@ export const loadUpdateCenterItems = async (
     apmEnabled && apmResult.code === 0
       ? parseApmUpgradableOutput(apmResult.stdout)
       : [];
+  console.log(`[UpdateCenter] parsed aptssItems count=${aptssItems.length}`, aptssItems.map((i) => `${i.pkgname} ${i.currentVersion}->${i.nextVersion}`));
+  console.log(`[UpdateCenter] parsed apmItems count=${apmItems.length}`, apmItems.map((i) => `${i.pkgname} ${i.currentVersion}->${i.nextVersion}`));
 
   const installedSources = buildInstalledSourceMap(
     aptssAvailable && aptssInstalledResult.code === 0
@@ -428,6 +440,7 @@ export const loadUpdateCenterItems = async (
       : "",
     apmInstalledResult.code === 0 ? apmInstalledResult.stdout : "",
   );
+  console.log(`[UpdateCenter] installedSources size=${installedSources.size}`);
 
   const [categorizedAptssItems, categorizedApmItems] = await Promise.all([
     aptssAvailable ? enrichItemCategories(aptssItems) : Promise.resolve([]),
@@ -441,13 +454,18 @@ export const loadUpdateCenterItems = async (
       ? enrichApmItems(categorizedApmItems, runCommand)
       : Promise.resolve({ items: [], warnings: [] }),
   ]);
+  console.log(`[UpdateCenter] enrichedAptssItems: count=${enrichedAptssItems.items.length}, warnings=${enrichedAptssItems.warnings.length}`, enrichedAptssItems.warnings);
+  console.log(`[UpdateCenter] enrichedApmItems: count=${enrichedApmItems.items.length}, warnings=${enrichedApmItems.warnings.length}`, enrichedApmItems.warnings);
+
+  const mergedItems = mergeUpdateSources(
+    enrichItemIcons(enrichedAptssItems.items),
+    enrichItemIcons(enrichedApmItems.items),
+    installedSources,
+  );
+  console.log(`[UpdateCenter] mergedItems count=${mergedItems.length}`, mergedItems.map((i) => `${i.pkgname} (${i.source}) ${i.currentVersion}->${i.nextVersion}`));
 
   return {
-    items: mergeUpdateSources(
-      enrichItemIcons(enrichedAptssItems.items),
-      enrichItemIcons(enrichedApmItems.items),
-      installedSources,
-    ),
+    items: mergedItems,
     warnings: [
       ...warnings,
       ...enrichedAptssItems.warnings,
diff --git a/electron/main/backend/update-center/query.ts b/electron/main/backend/update-center/query.ts
index def20b47..9b4a7899 100644
--- a/electron/main/backend/update-center/query.ts
+++ b/electron/main/backend/update-center/query.ts
@@ -262,10 +262,19 @@ const compareVersions = (left: string, right: string): number => {
 
 export const parseAptssUpgradableOutput = (
   output: string,
-): UpdateCenterItem[] => parseUpgradableOutput(output, "aptss");
+): UpdateCenterItem[] => {
+  console.log(`[UpdateCenter] parseAptssUpgradableOutput input (first 1000 chars): ${output.substring(0, 1000)}`);
+  const result = parseUpgradableOutput(output, "aptss");
+  console.log(`[UpdateCenter] parseAptssUpgradableOutput result count=${result.length}`);
+  return result;
+};
 
-export const parseApmUpgradableOutput = (output: string): UpdateCenterItem[] =>
-  parseUpgradableOutput(output, "apm");
+export const parseApmUpgradableOutput = (output: string): UpdateCenterItem[] => {
+  console.log(`[UpdateCenter] parseApmUpgradableOutput input (first 1000 chars): ${output.substring(0, 1000)}`);
+  const result = parseUpgradableOutput(output, "apm");
+  console.log(`[UpdateCenter] parseApmUpgradableOutput result count=${result.length}`);
+  return result;
+};
 
 export const parsePrintUrisOutput = (
   output: string,
@@ -273,8 +282,11 @@ export const parsePrintUrisOutput = (
   UpdateCenterItem,
   "downloadUrl" | "fileName" | "size" | "sha512"
 > | null => {
-  const match = output.trim().match(PRINT_URIS_PATTERN);
+  const trimmed = output.trim();
+  console.log(`[UpdateCenter] parsePrintUrisOutput input (first 500 chars): ${trimmed.substring(0, 500)}`);
+  const match = trimmed.match(PRINT_URIS_PATTERN);
   if (!match) {
+    console.log(`[UpdateCenter] parsePrintUrisOutput: no match found for pattern ${PRINT_URIS_PATTERN}`);
     return null;
   }
 
diff --git a/electron/main/backend/update-center/service.ts b/electron/main/backend/update-center/service.ts
index 2ac6f785..2a425293 100644
--- a/electron/main/backend/update-center/service.ts
+++ b/electron/main/backend/update-center/service.ts
@@ -166,22 +166,27 @@ export const createUpdateCenterService = (
     storeFilter: StoreFilter = currentStoreFilter,
   ): Promise<UpdateCenterServiceState> => {
     currentStoreFilter = storeFilter;
+    console.log(`[UpdateCenter] service.refresh called with storeFilter=${storeFilter}`);
     queue.startRefresh();
     emit();
 
     try {
       const ignoredEntries = await loadIgnored();
+      console.log(`[UpdateCenter] ignoredEntries count=${ignoredEntries.size}`);
       const loadedItems = normalizeLoadedItems(
         await options.loadItems(currentStoreFilter),
       );
+      console.log(`[UpdateCenter] loadItems returned: items=${loadedItems.items.length}, warnings=${loadedItems.warnings.length}`, loadedItems.warnings);
       const items = sortIgnoredItems(
         applyIgnoredEntries(loadedItems.items, ignoredEntries),
       );
+      console.log(`[UpdateCenter] after applying ignored: items=${items.length}`);
       queue.setItems(items);
       queue.finishRefresh(loadedItems.warnings);
       return emit();
     } catch (error) {
       const message = error instanceof Error ? error.message : String(error);
+      console.error(`[UpdateCenter] refresh error:`, error);
       queue.setItems([]);
       applyWarning(message);
       return emit();
diff --git a/src/__tests__/unit/update-center/load-items.test.ts b/src/__tests__/unit/update-center/load-items.test.ts
index b231bc2a..5e8fdaef 100644
--- a/src/__tests__/unit/update-center/load-items.test.ts
+++ b/src/__tests__/unit/update-center/load-items.test.ts
@@ -11,7 +11,7 @@ type RemoteStoreResponse =
   | Array<Record<string, unknown>>;
 
 const APTSS_LIST_UPGRADABLE_KEY =
-  "bash -lc env LANGUAGE=en_US aptss list --upgradable";
+  "bash -lc env LANGUAGE=en_US /usr/bin/apt -c /opt/durapps/spark-store/bin/apt-fast-conf/aptss-apt.conf list --upgradable -o Dir::Etc::sourcelist=/opt/durapps/spark-store/bin/apt-fast-conf/sources.list.d/aptss.list -o Dir::Etc::sourceparts=/dev/null -o APT::Get::List-Cleanup=0 | awk 'NR>1'";
 
 const DPKG_QUERY_INSTALLED_KEY =
   "dpkg-query -W -f=${Package}\t${db:Status-Want} ${db:Status-Status} ${db:Status-Eflag}\n";
@@ -191,7 +191,7 @@ describe("update-center load items", () => {
       ],
     });
 
-    const result = await loadUpdateCenterItems(async (command, args) => {
+    const result = await loadUpdateCenterItems("both", async (command, args) => {
       const key = `${command} ${args.join(" ")}`;
       const match = commandResults.get(key);
       if (!match) {
@@ -233,7 +233,7 @@ describe("update-center load items", () => {
       ],
     });
 
-    const result = await loadUpdateCenterItems(async (command, args) => {
+    const result = await loadUpdateCenterItems("both", async (command, args) => {
       const key = `${command} ${args.join(" ")}`;
 
       if (key === WHICH_APTSS_KEY) {
@@ -360,7 +360,7 @@ describe("update-center load items", () => {
       throw new Error(`Unexpected command ${key}`);
     };
 
-    const firstResult = await loadUpdateCenterItems(runCommand);
+    const firstResult = await loadUpdateCenterItems("both", runCommand);
 
     expect(firstResult.items).toEqual([
       {
@@ -384,7 +384,7 @@ describe("update-center load items", () => {
       "https://erotica.spark-app.store/amd64-store/office/applist.json"
     ] = [{ Name: "Spark Notes", Pkgname: "spark-notes" }];
 
-    const secondResult = await loadUpdateCenterItems(runCommand);
+    const secondResult = await loadUpdateCenterItems("both", runCommand);
 
     expect(secondResult.items).toEqual([
       {
@@ -416,7 +416,7 @@ describe("update-center load items", () => {
       ],
     });
 
-    const result = await loadUpdateCenterItems(async (command, args) => {
+    const result = await loadUpdateCenterItems("both", async (command, args) => {
       const key = `${command} ${args.join(" ")}`;
 
       if (key === WHICH_APTSS_KEY) {
@@ -531,7 +531,7 @@ describe("update-center load items", () => {
       throw new Error(`Unexpected command ${key}`);
     });
 
-    await loadUpdateCenterItems(runCommand, "apm");
+    await loadUpdateCenterItems("apm", runCommand);
 
     expect(runCommand).not.toHaveBeenCalledWith(
       "bash",
@@ -590,7 +590,7 @@ describe("update-center load items", () => {
       throw new Error(`Unexpected command ${key}`);
     });
 
-    await loadUpdateCenterItems(runCommand, "spark");
+    await loadUpdateCenterItems("spark", runCommand);
 
     expect(runCommand).not.toHaveBeenCalledWith("apm", [
       "list",