diff --git a/.gitea/workflows/release.yml b/.gitea/workflows/release.yml
index bfc45f8..b4e6918 100644
--- a/.gitea/workflows/release.yml
+++ b/.gitea/workflows/release.yml
@@ -78,7 +78,26 @@ jobs:
           REPOSITORY: ${{ gitea.repository }}
         run: |
           set -eu
-          upload_url="${SERVER_URL%/}/api/v1/repos/$REPOSITORY/releases/$RELEASE_ID/assets"
+          release_url="${SERVER_URL%/}/api/v1/repos/$REPOSITORY/releases/$RELEASE_ID"
+          upload_url="$release_url/assets"
+          release_json="$(curl -fsS -H "Authorization: token $GITEA_TOKEN" "$release_url")"
+
+          delete_asset_if_exists() {
+            asset_name="$1"
+            asset_id="$(printf '%s' "$release_json" \
+              | tr '{' '\n' \
+              | grep "\"name\":\"$asset_name\"" \
+              | sed -n 's/.*"id":[[:space:]]*\([0-9][0-9]*\).*/\1/p' \
+              | head -n 1)"
+            if [ -n "$asset_id" ]; then
+              curl -fsS -X DELETE "$upload_url/$asset_id" \
+                -H "Authorization: token $GITEA_TOKEN"
+            fi
+          }
+
+          delete_asset_if_exists "$RELEASE_ARCHIVE"
+          delete_asset_if_exists "$RELEASE_SHA256"
+
           curl -fsS -X POST "$upload_url?name=$RELEASE_ARCHIVE" \
             -H "Authorization: token $GITEA_TOKEN" \
             -F "attachment=@$RELEASE_ARCHIVE"
diff --git a/src/commands/update.rs b/src/commands/update.rs
index 169c4b1..a6a988d 100644
--- a/src/commands/update.rs
+++ b/src/commands/update.rs
@@ -116,17 +116,16 @@ fn update(force: bool) -> Result<UpdateResult, String> {
          curl -fsSL {} -o \"$tmp/openstock.tar.gz\"\n\
          tar -xzf \"$tmp/openstock.tar.gz\" -C \"$tmp\"\n\
          test -x \"$tmp/openstock\"\n\
-         mkdir -p {}\n\
-         target={}\n\
-         tmp_target=\"{}/.openstock.tmp.$$\"\n\
+         install_dir={}\n\
+         mkdir -p \"$install_dir\"\n\
+         target=\"$install_dir/openstock\"\n\
+         tmp_target=\"$install_dir/.openstock.tmp.$$\"\n\
          cp \"$tmp/openstock\" \"$tmp_target\"\n\
          chmod 755 \"$tmp_target\"\n\
          mv -f \"$tmp_target\" \"$target\"\n\
          printf 'installed: %s\\n' \"$target\"\n",
         shell_quote(&asset.browser_download_url),
         shell_quote(&install_dir.display().to_string()),
-        shell_quote(&install_dir.join("openstock").display().to_string()),
-        shell_quote(&install_dir.display().to_string()),
     );
     let output = Command::new("sh")
         .arg("-c")