diff --git a/.gitea/workflows/cd.yaml b/.gitea/workflows/cd.yaml
index 495f7b63..67edba08 100644
--- a/.gitea/workflows/cd.yaml
+++ b/.gitea/workflows/cd.yaml
@@ -79,9 +79,9 @@ jobs:
 
           if [ ! -d "$VENV" ] || [ "$(cat $HASH_FILE 2>/dev/null)" != "$CURRENT_HASH" ]; then
             echo "📦 deps 已變更，重建 venv..."
-            # 確保 python3-venv 已安裝（runner image 可能未內建）
-            # 2026-04-05 Claude Code: 改為先安裝再建立，避免 || 邏輯在 set -e 下失效
-            apt-get install -y -q python3.11-venv 2>/dev/null || apt-get install -y -q python3-venv 2>/dev/null || true
+            # 確保 python3-venv 已安裝（node:20-bookworm 有 python3.11 但需先 apt-get update）
+            # 2026-04-05 Claude Code: apt-get update 必須在 install 前，否則 apt cache 空導致安裝失敗
+            apt-get update -q && apt-get install -y -q python3.11-venv || apt-get install -y -q python3-venv
             rm -rf "$VENV"
             python3 -m venv $VENV
             source $VENV/bin/activate