Hi,

On Fri, 07 Jun 2019 at 09:56:52 +0100, Dominic Raferd wrote:
> On Wed, 29 May 2019 at 14:44, Guilhem Moulin <guilhem@fripost.org> wrote:
>> I guess that if you want to stick to decrypt_derived your options are
>> to use `luksFormat --type luks1` (or `convert --type luks1`);
> 
> unfortunately this doesn't work. I try it (booting from SystemRescueCD):
> 
> # cryptsetup convert /dev/sda5 --type luks1
> […] 
> Cannot convert to LUKS1 format - keyslot 0 is not LUKS1 compatible.

For LUKS1, the only supported PBKDF algorithm is PBKDF2 (while for LUKS2
it defaults to argon2i), you therefore need to remove existing
non-PBKDF2 keyslots with `cryptsetup luksKillSlot`, or convert them with
`cryptsetup luksConvertKey --pbkdf pbkdf2`.

Cheers,
-- 
Guilhem.