Once, out of curiousity, I read the EPROM of a commercial packet-radio TNC.
I was surprised to find no ASCII text in it. I suspected the data bit lines
had been jumbled up. There are two reasons to do this:

1. It obstructs people reverse engineering.
But anyone can do as I did and buzz the connections between the CPU (a 63B01)
and the EPROM bits. I wrote a tiny C program to read in the file, unjumble
the bits, and writie it back. Presto! Readable ASCII and program code.

2. It is convenient for circuit-board layout.
It's worth doing if it means the difference between single & double-sided PCBs.

If you don't have the original hardware, you'll have to experiment.
I think there are 8x7x6x5x4x3x2x1 = 40320 possible combinations.

If they were really sneaky, they could jumble address lines too!