How to make a backup of kickstart 1.2 and 1.3 disks?

[Jope]

Forget xcopy, open a shell/cli and:

diskcopy from df0: to df1:

or for a one drive system:

diskcopy from df0: to df0:

There's nothing fishy in the KS disk, it's written out in a totally standard way (but of course doesn't contain a filesystem). No need for any nibble modes, they're normal Amiga tracks.