Can be fixed in initramfs-tools like this:
git diff init
diff --git a/init b/init
index 9552e5c..82f1cb1 100755
--- a/init
+++ b/init
@@ -236,6 +236,12 @@ if read_fstab_entry /usr; then
log_end_msg
fi
+if read_fstab_entry /usr/lib; then
+ log_begin_msg "Mounting /usr/lib file system"
+ mountfs /usr/lib
+ log_end_msg
+fi
+
# Mount cleanup
mount_bottom
nfs_bottom