diff --git a/Makefile-rpm-ostree.am b/Makefile-rpm-ostree.am
index 217748b5..1caa48ed 100644
--- a/Makefile-rpm-ostree.am
+++ b/Makefile-rpm-ostree.am
@@ -29,7 +29,7 @@ rpm_ostree_SOURCES = src/app/main.cxx \
 	src/app/rpmostree-builtin-cancel.cxx \
 	src/app/rpmostree-builtin-cliwrap.cxx \
 	src/app/rpmostree-builtin-cleanup.cxx \
-	src/app/rpmostree-builtin-initramfs.c \
+	src/app/rpmostree-builtin-initramfs.cxx \
 	src/app/rpmostree-builtin-initramfs-etc.c \
 	src/app/rpmostree-builtin-livefs.cxx \
 	src/app/rpmostree-builtin-usroverlay.cxx \
diff --git a/src/app/rpmostree-builtin-initramfs.c b/src/app/rpmostree-builtin-initramfs.cxx
similarity index 100%
rename from src/app/rpmostree-builtin-initramfs.c
rename to src/app/rpmostree-builtin-initramfs.cxx