On my hp Spectre x360, the Ins key is only reachable via the Fn key as in Fn+PrtScr.

So I wanted to swap both keys. System-wide - so not only in X (using xev).

I finally found this which suggested the following procedure:

  1. Dump the current keyboard layout:

    sudo dumpkeys > backup.kmap
  2. Check the keycodes you want to change (Ins = 110, PrtScr = 99):

    sudo showkey

    (When you're done, wait 10 seconds for it to exit automatically.)

  3. Copy the dumped keyboard layout:

    cp backup.kmap ins-prt-swap.kmap
  4. Edit it to swap all occurrences of 99 to 110 and vice versa, e.g. change:

    keycode  99 = ...
    ...
    keycode 110 = Insert.....

    to

    keycode 110 = ...
    ...
    keycode  99 = Insert.....
  5. The suggested sudo setcon --save didn't work for me, but Ubuntu loads the active keymap from the file /etc/console-setup/cached.kmap.gz. So I gzipped my ins-prt-swap.kmap and copied the resulting ins-prt-swap.kmap.gz to /etc/console-setup/cached.kmap.gz.