Hi Ludo,

On Mon, 13 May 2019 23:51:46 +0200
Ludovic Courtès <ludo@gnu.org> wrote:

> Giovanni Biscuolo <g@xelera.eu> skribis:
> 
> > summary: AFAIU the installer lacks "force" formatting when using btrfs,
> > using "mkfs.btrfs -f <device>" solved the problem (see below)  
> 
> I believe the patch at <https://issues.guix.info/issue/35657> fixes it.
> Danny?

I haven't tested it but it should work.

I've pushed that patch to master now.