Subject: bug#26339: [PATCH 17/18] scripts: system: Adapt "switch-generation" to new bootloader API.

From: Mathieu Othacehe <[email-masked]>
Date: Fri, 05 May 2017 09:21:04 +0200

Hey Danny !

> Ah, so this is trying to restore the correct bootloader to the correct device, should the user have switched bootloader of the guix system and then switched back.

That's it.

> What happens if the user switches to an old generation which doesn't have this new-style parameters file?

Well, by default the bootloader is assumed to be grub (because grub is
the only supported bootloader in pre-rework guix).

For the boot-device, it is set to #f if not read in parameter
file. During a switch-genereation if boot-device is #f, the
configuration is updated, but the bootloader is not reinstalled.

It was already what happended before my rework. The bootloader was not
reinstalled because we cannot be certain to reinstall the same grub
version as the one installed.

Mathieu