Subject: Re: bug#27007: [PATCH 2/2] doc: Adapt to multiple bootloader support.

From: Danny Milosavljevic <[email-masked]>
Date: Mon, 5 Jun 2017 16:11:57 +0200

Hi Ludo,

On Mon, 05 Jun 2017 12:36:28 +0200
[email-masked] (Ludovic Courtès) wrote:

> What happens with other bootloaders?  Do we get older boot entries?

Yes, but U-Boot has no support for submenus, only one menu [1].  Extlinux-the-format technically does support submenus [2].

> >  @item switch-generation

> What happens to the bootloader itself?  Does it change the bootloader to
> the one that was chosen back then?

No.  We had been thinking about it but it's unsafe to do that.

So instead switch-generation will always reuse the bootloader that was used in the current generation.

switch-generation has the same effect as manually selecting another menu entry from the boot menu on bootup would have had - it just additionally defaults to that entry.

On the other hand, when you run "guix system reconfigure" or "guix system init":  There, it will install and use the (newly) specified one.

[1] See also <https://github.com/u-boot/u-boot/blob/master/cmd/bootmenu.c>.
[2] See also <http://www.syslinux.org/wiki/index.php?title=Menu#MENU_BEGIN>.