Maybe there is an (unsupported) way to do it after all…
However, if you decide to go this route please try it out on a test system first and only apply it on your production server if you really know what you are doing and if you know how to undo it if you encounter any problems.
See here: External storage as default landing page - #8 by jtr
…and here: External storage as default landing page - #10 by jtr