Enable KDF-DO on a populated GNUK

[Szczepan Zalega | Nitrokey]

Hello,

>From my tests it turned out that currently with the recent GNUK 1.2.15
and GnuPG 2.2.25 it is not possible to set up a KDF-DO on a populated /
personalized device (with keys). As a user I would like to have such
option, so I would not be forced through factory reset.

On requesting KDF setting in such case GNUK replies with:
```
2021-01-26 12:35:05 scdaemon[22] DBG:  response: sw=6F00  datalen=0
2021-01-26 12:35:05 scdaemon[22] failed to set 'KDF': Card error
```

Is having this GnuPG [1] patch sufficient to make that work, or are
there any changes needed in the GNUK itself?

Best regards,
Szczepan


[1] https://dev.gnupg.org/T3891

-- 
Szczepan Zalega
Senior Software Developer

Nitrokey GmbH
https://www.nitrokey.com

Email: szczepan at nitrokey.com
Nickname: szszszsz

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