diff --git a/README.rst b/README.rst
index 45d63ed..8e87e40 100644
--- a/README.rst
+++ b/README.rst
@@ -96,24 +96,26 @@ from its values as ``DOCKER_IMAGE_REPO:MAIN_APP-VERSION-SHA_SHORT``; use
 ``--docker-image=quay.io/vauxoo/PROJECT:TAG`` to pick the image pushed by the
 ``build_docker`` pipeline instead.
 
-Optional tools (``--build-env-args``)
-=====================================
+Optional build steps (``--build-env-args``)
+===========================================
 
-Some development tools are **not** installed by default. They are enabled with
-a flag passed as a build environment variable using ``--build-env-args``, which
-generates an ``ENV <FLAG>=TRUE`` line in the Dockerfile. If the flag is not
-defined, the installation step is skipped.
+Some development tools and build steps are **not** enabled by default. They are
+enabled with a flag passed as a build environment variable using
+``--build-env-args``, which generates an ``ENV <FLAG>=TRUE`` line in the
+Dockerfile. If the flag is not defined, the step is skipped.
 
 .. list-table::
     :widths: 30 70
     :header-rows: 1
 
     * - Flag
-      - Installs
+      - Enables
     * - ``VIM_INSTALL``
       - vim + spf13-vim, vim-openerp, jedi-vim, wakatime and the pylint_odoo/eslint syntastic configuration
     * - ``ZSH_INSTALL``
       - zsh + oh-my-zsh with the ``odoo-shippable`` theme
+    * - ``CHOWN_UID_GID``
+      - Aligns the odoo user UID/GID to 5410 to match OrchestSH images. Slow: it re-chowns the whole filesystem
 
 Example enabling more than one::
 
diff --git a/src/travis2docker/templates/build.sh b/src/travis2docker/templates/build.sh
index 9f59b3a..a52596d 100644
--- a/src/travis2docker/templates/build.sh
+++ b/src/travis2docker/templates/build.sh
@@ -220,21 +220,35 @@ set_odoo_ids(){
     # OrchestSH images (ORCHESTSH=True) use UID/GID 5410 for the odoo user;
     # older images use 1000/1001. A mismatch causes permission issues when
     # sharing files across containers, so align both to 5410 when they differ.
+    if [ -z ${CHOWN_UID_GID+x} ];
+    then
+      echo "CHOWN_UID_GID was not defined. Skipping odoo UID/GID alignment. Use t2d parameter --build-env-args=CHOWN_UID_GID to be autoconfigured."
+      return 0;
+    fi
     CURRENT_UID=$(id -u odoo)
     CURRENT_GID=$(id -g odoo)
     NEW_ID=5410
+    if [ "${CURRENT_UID}" = "${NEW_ID}" ] && [ "${CURRENT_GID}" = "${NEW_ID}" ]; then
+        echo "odoo UID/GID already set to ${NEW_ID}. Nothing to do."
+        return 0;
+    fi
     if [ "${CURRENT_GID}" != "${NEW_ID}" ]; then
         echo "Changing odoo GID from ${CURRENT_GID} to ${NEW_ID}"
         groupmod -g "${NEW_ID}" odoo
-        # groupmod does not re-chown any file
-        find / -xdev -gid "${CURRENT_GID}" -exec chown -h ":${NEW_ID}" {} + 2>/dev/null || true
     fi
     if [ "${CURRENT_UID}" != "${NEW_ID}" ]; then
         echo "Changing odoo UID from ${CURRENT_UID} to ${NEW_ID}"
         usermod -u "${NEW_ID}" odoo
-        # usermod only re-chowns files inside the home directory
-        find / -xdev -uid "${CURRENT_UID}" -exec chown -h "${NEW_ID}" {} + 2>/dev/null || true
     fi
+    # groupmod does not re-chown any file and usermod only re-chowns files inside
+    # the home directory, so the leftovers are re-chowned here. Both predicates are
+    # evaluated in a single filesystem traversal using the "," operator: walking the
+    # whole filesystem twice is what makes this step slow. The branch whose ID did
+    # not change simply re-applies the very same ID, so it is a no-op.
+    find / -xdev \
+        \( -uid "${CURRENT_UID}" -exec chown -h "${NEW_ID}" {} + \) , \
+        \( -gid "${CURRENT_GID}" -exec chown -h ":${NEW_ID}" {} + \) \
+        2>/dev/null || true
 }
 
 configure_vim(){
diff --git a/src/travis2docker/travis2docker.py b/src/travis2docker/travis2docker.py
index f42102b..e2a4781 100644
--- a/src/travis2docker/travis2docker.py
+++ b/src/travis2docker/travis2docker.py
@@ -135,7 +135,7 @@ def copy_path(self, path):
         if src.is_dir():
             try:
                 shutil.copytree(src, dest_path)
-            except shutil.Error:  # pylint: disable=except-pass
+            except shutil.Error:  # ruff: ignore[except-pass]
                 pass  # There are permissions errors to copy
         elif src.is_file():
             shutil.copy(src, dest_path)