take it apart down to component level and re fit with the sprockets flipped over.
i know the ramps and pins wont work, but does it still change gear well enough?

i run a 1×8 set up and get double the use out of my front chainring this way…

**** knows. You'll need a new small cog

It wouldn't fit onto the splines of the rear hub – the thinner spline is not symetrically placed between the ones either side of it, so you can't fit the sprockets backwards.

Does work with some singlespeed and aftermarket sprockets without the single thinner spline shimano use to ensure that all the sprockets line up for optimum shifting.

good point, or just loose the last gear, pack it with spacers and adjust the rear mech bottom stop.

nice shout paule.
didnt think of that.

what i do is only use the odd gears (1st 3rd …) in winter then the even gears in summer.

😀

Sounds like you're ready for an Alfine or Rohloff

Marchisio