Using two bytes (PBP alias) I don’t think costs you any time even behind the scenes,
and then just addressing them in the order you want would be the next best thing to swapping the hardware.
I’m not familiar with the device, but if REV didn’t work as you expected, it sound like swapping bytes was the solution?

If that’s wrong, and it’s back to reversing bits, there’s no math to do it,
it’s always whacky procedural code emulating what a Human would do.
You can use the above method first (almost free), and then logical operators,
but it’s essentially the same goal as moving a ball around a table with paper cups.