Hello Guix,

thanks to commit

commit 26c1bd9dfafb5a954d2174b7a000304cd7ae6345
Author: Tobias Geerinckx-Rice <me@tobias.gr>
Date:   Mon Apr 6 17:48:21 2020 +0200

    vm: Transparently compress iso9660 images.
    
    * gnu/build/vm.scm (make-iso9660-image): Use the ‘--zisofs’ xorriso
    filter at the highest compression settings for supported directories.

it was possible to burn the Guix System install image to a 700MB CD.
But it fits no more.  I compared using the du tool (comparison between
good old Guix version e427593 and bad new Guix version 3734857f (with
unmerged installer patches) is attached).  The result is that most
packages got slightly bigger and this broke the camel’s back.  From what
Tobias (Cc) wrote, he used the highest compression settings.

So it seems nothing can be done to make the install iso smaller than
700MB and support this antiquated storage medium, but I thought I’d open
a bug and ask, because my laptop doesn’t boot from USB, I have more
CD/Rs than DVD/Rs and I guess they are cheaper than DVD.

Regards,
Florian