Fai.me failed minimal install when GUI and non-free are enable

[Thomas Lange]

>>>>> On Fri, 10 Jul 2020 15:24:53 +0200 (CEST), Jean-mathieu CHANTREIN <jean-mathieu.chantrein at univ-angers.fr> said:

    > I'll try to use fai.me to generate an iso with GUI and some package. 
    > After some tests, I think there is a problem with the simultaneous use of non-free and GUI enable (and may be backports enable to).

    > A minimal install with no GUI, non-free and backports enable work.
    > A minimal install with GUI and backports work.
    > But, with a minimal install with GUI, non-free and backports enable, there is a dependancy problem when fai install non-free package (linux-image-amd64: Depends linux-image-5.6.0-0.bpo.2-amd64 [...] but it is not going to be installed) 
    > You can see error.log and software.log at 1'20 and 2'28 in this virtualbox record output here: https://drive.google.com/file/d/1M5bYxdHOiw0DerFxNmjwigD8utpPkuuS/view?usp=sharing
    > or reproduce the error with the ISO defined below.

    > Have you ever had this type of problem with fai.me and if so, how did you fix it?
Salut Jean-mathieu,

I finally found the strange bug.
The kernel package from buster backports breaks if the version of the
wireless-regdb package from stable is installed. This is what happens
in your config because the Gnome enviroment or the nonfree firmware
will install wireless-regdb from stable.

It's very hard to get the correct package list in this special
situation. Therefore I found a simple fix, which adds wireless-regdb
into the backports config.

The technical details are more complicated and not in FAI itself, but
IMO this workaround is simple and works. A test using a new FAI.me
image showed no problems now.

--
regards Thomas