diff --git a/taskcluster/docker/update-verify/Dockerfile b/taskcluster/docker/update-verify/Dockerfile
index 92432e99626a..96dca1b47d42 100644
--- a/taskcluster/docker/update-verify/Dockerfile
+++ b/taskcluster/docker/update-verify/Dockerfile
@@ -22,10 +22,8 @@ RUN bash /tmp/system-setup.sh
 RUN chown -R worker:worker /builds/worker/bin && chmod 755 /builds/worker/bin/*
 ENV PATH $PATH:/builds/worker/bin
 
-# Set variable normally configured at login, by the shells parent process, these
-# are taken from GNU su manual
-ENV           LANG          en_US.UTF-8
-ENV           LC_ALL        en_US.UTF-8
+ENV           LANG          C.UTF-8
+ENV           LC_ALL        C.UTF-8
 
 # Set a default command useful for debugging
 CMD ["/bin/bash", "--login"]
diff --git a/taskcluster/docker/update-verify/system-setup.sh b/taskcluster/docker/update-verify/system-setup.sh
index 8a55f255f879..d6d144aa674e 100644
--- a/taskcluster/docker/update-verify/system-setup.sh
+++ b/taskcluster/docker/update-verify/system-setup.sh
@@ -18,11 +18,6 @@ apt_packages+=('sudo')
 apt-get update
 apt-get install "${apt_packages[@]}"
 
-# Without this we get spurious "LC_ALL: cannot change locale (en_US.UTF-8)" errors,
-# and python scripts raise UnicodeEncodeError when trying to print unicode characters.
-locale-gen en_US.UTF-8
-dpkg-reconfigure locales
-
 su -c 'git config --global user.email "worker@mozilla.test"' worker
 su -c 'git config --global user.name "worker"' worker
 
diff --git a/taskcluster/kinds/docker-image/kind.yml b/taskcluster/kinds/docker-image/kind.yml
index 68163aefcaad..e5f18ef85473 100644
--- a/taskcluster/kinds/docker-image/kind.yml
+++ b/taskcluster/kinds/docker-image/kind.yml
@@ -254,7 +254,7 @@ tasks:
         symbol: I(pg)
     update-verify:
         symbol: I(uv)
-        parent: ubuntu2004-base
+        parent: debian12-base
     diffoscope:
         symbol: I(diff)
         parent: debian12-base