ci retry package downloads serially

.github/workflows/X-x86_64_X.yml

@@ -252,7 +252,14 @@ jobs:
         cd openwrt
         ./scripts/feeds install -a
         make defconfig
-        make download -j${DOWNLOAD_JOBS}
+        mkdir -p dl
+        if ! make download -j${DOWNLOAD_JOBS}
+        then
+            echo "Parallel package download failed; retrying serially with verbose output."
+            find dl -type f -size -1024c -print -delete
+            make download -j1 V=s
+        fi
+        find dl -type f -size -1024c -print -delete
 
     - name: Build OpenWrt
       run: |

.github/workflows/X-x86_64_Y.yml

@@ -249,7 +249,14 @@ jobs:
         cd openwrt
         ./scripts/feeds install -a
         make defconfig
-        make download -j${DOWNLOAD_JOBS}
+        mkdir -p dl
+        if ! make download -j${DOWNLOAD_JOBS}
+        then
+            echo "Parallel package download failed; retrying serially with verbose output."
+            find dl -type f -size -1024c -print -delete
+            make download -j1 V=s
+        fi
+        find dl -type f -size -1024c -print -delete
 
     - name: Build OpenWrt
       run: |

.github/workflows/X-x86_64_Z.yml

@@ -247,7 +247,14 @@ jobs:
         cd openwrt
         ./scripts/feeds install -a
         make defconfig
-        make download -j${DOWNLOAD_JOBS}
+        mkdir -p dl
+        if ! make download -j${DOWNLOAD_JOBS}
+        then
+            echo "Parallel package download failed; retrying serially with verbose output."
+            find dl -type f -size -1024c -print -delete
+            make download -j1 V=s
+        fi
+        find dl -type f -size -1024c -print -delete
 
     - name: Build OpenWrt
       run: |

AI_CHANGELOG_GRUB2_DOWNLOAD_RETRY.md

@@ -0,0 +1,20 @@
+# AI Modification Log: GRUB2 Download Retry
+
+Date: 2026-06-29
+
+## Summary
+
+- Updated the X/Y/Z x86_64 workflows so `make download` retries serially with `V=s` after a parallel download failure.
+- Added cleanup for tiny incomplete files in `dl/` before the retry and after download completion.
+- Updated `CODEX_HANDOFF.md` to record that the config-comment task was interrupted by this build failure fix.
+
+## Reason
+
+The reported failure stopped at `package/boot/grub2` with build variant `efi` during `make package/download`. Retrying `make download` serially follows the OpenWrt error guidance and avoids common parallel download or cached partial-file failures while preserving detailed logs if the upstream package still fails.
+
+## Verification
+
+- Inspected the workflow diff and confirmed only the X/Y/Z pre-download blocks changed.
+- Parsed the edited X/Y/Z workflow files with PyYAML.
+- Checked workflow line endings and confirmed X stayed LF while Y/Z stayed CRLF.
+- Ran whitespace validation with `git -c core.whitespace=blank-at-eol,blank-at-eof,space-before-tab,cr-at-eol diff --check` because Y/Z intentionally still use CRLF.

CODEX_HANDOFF.md

@@ -13,7 +13,7 @@ This file is the stable restart point for future Codex sessions in this reposito
 - Remote tracking branch: `origin/ai`
 - Latest completed task batch: continued the GitHub Actions X/Y/Z optimization backlog through multiple high-priority and low-risk maintainability/script items.
 - Latest task commit at handoff update time: `1629605 docs update codex handoff`
-- Current requested task: update the todo handoff, then add comments to `Configs/x86_64-X`, `Configs/x86_64-Y`, and `Configs/x86_64-Z`, plus a dedicated config optimization todo list.
+- Current requested task: fixed a reported `package/boot/grub2` EFI failure during `make download` by adding a serial verbose retry path; resume #35 after this fix is committed.
 - Backlog file: `NOTES_GHA_XYZ_OPTIMIZATION.md`
 
 ## Completed Backlog Items
@@ -48,6 +48,7 @@ Each code fix has a corresponding `AI_CHANGELOG_*.md` file.
 
 Immediate continuation:
 
+- Build failure fix completed: X/Y/Z pre-download now retries serially with `V=s` after a parallel package download failure, and cleans tiny incomplete files from `dl/`.
 - #35: Document the X/Y/Z x86_64 config intent. Add header comments to `Configs/x86_64-X`, `Configs/x86_64-Y`, and `Configs/x86_64-Z`, then list config-specific optimization points as todos.
 
 The next unresolved backlog items need broader design or more careful behavior decisions: