diff --git a/src/libotcore/otcore.h b/src/libotcore/otcore.h
index 4d51398e6a..32a162dc1e 100644
--- a/src/libotcore/otcore.h
+++ b/src/libotcore/otcore.h
@@ -60,6 +60,10 @@ GKeyFile *otcore_load_config (int rootfs, const char *filename, GError **error);
 // The directory holding the root overlayfs
 #define OSTREE_DEPLOYMENT_ROOT_TRANSIENT_DIR "root-transient"
 
+#define OTCORE_SYSROOT_NOT_WRITEABLE \
+  "sysroot.readonly=true requires %s to be writable at this point, the cmdline should contain rw " \
+  "but not ro, if that is not the case this is likely the issue"
+
 // The name of the composefs metadata root
 #define OSTREE_COMPOSEFS_NAME ".ostree.cfs"
 // The temporary directory used for the EROFS mount; it's in the .private directory
diff --git a/src/switchroot/ostree-prepare-root-static.c b/src/switchroot/ostree-prepare-root-static.c
index 4aaa469246..ce3340f83d 100644
--- a/src/switchroot/ostree-prepare-root-static.c
+++ b/src/switchroot/ostree-prepare-root-static.c
@@ -229,8 +229,7 @@ main (int argc, char *argv[])
   if (sysroot_readonly)
     {
       if (!sysroot_currently_writable)
-        errx (EXIT_FAILURE, "sysroot.readonly=true requires %s to be writable at this point",
-              root_arg);
+        errx (EXIT_FAILURE, OTCORE_SYSROOT_NOT_WRITEABLE, root_arg);
       /* Pass on the fact that we discovered a readonly sysroot to ostree-remount.service */
       int fd = open (_OSTREE_SYSROOT_READONLY_STAMP, O_WRONLY | O_CREAT | O_CLOEXEC, 0644);
       if (fd < 0)
diff --git a/src/switchroot/ostree-prepare-root.c b/src/switchroot/ostree-prepare-root.c
index 8d0ab88e44..1a0539e190 100644
--- a/src/switchroot/ostree-prepare-root.c
+++ b/src/switchroot/ostree-prepare-root.c
@@ -557,8 +557,7 @@ main (int argc, char *argv[])
   if (sysroot_readonly)
     {
       if (!sysroot_currently_writable)
-        errx (EXIT_FAILURE, "sysroot.readonly=true requires %s to be writable at this point",
-              root_arg);
+        errx (EXIT_FAILURE, OTCORE_SYSROOT_NOT_WRITEABLE, root_arg);
     }
   /* Pass on the state for use by ostree-prepare-root */
   g_variant_builder_add (&metadata_builder, "{sv}", OTCORE_RUN_BOOTED_KEY_SYSROOT_RO,