diff --git a/mathcomp/dual/Dockerfile b/mathcomp/dual/Dockerfile
index 6d4a129..fa4975b 100644
--- a/mathcomp/dual/Dockerfile
+++ b/mathcomp/dual/Dockerfile
@@ -34,7 +34,3 @@ RUN set -x \
   && opam install -y -j "${NJOBS}" ${MATHCOMP_PACKAGE} \
   && opam clean -a -c -s --logs \
   && opam config list && opam list
-
-# Restore default shell to fully preserve backward compatibility
-SHELL ["/bin/sh", "-c"]
-# Still, we may remove this line later on.
diff --git a/mathcomp/single/Dockerfile b/mathcomp/single/Dockerfile
index fcce161..8b986b4 100644
--- a/mathcomp/single/Dockerfile
+++ b/mathcomp/single/Dockerfile
@@ -20,7 +20,3 @@ RUN set -x \
   && opam install -y -j "${NJOBS}" ${MATHCOMP_PACKAGE} \
   && opam clean -a -c -s --logs \
   && opam config list && opam list
-
-# Restore default shell to fully preserve backward compatibility
-SHELL ["/bin/sh", "-c"]
-# Still, we may remove this line later on.