SHA2 digest on gpg smartcard

[Laurent Bigonville]

Hi,

I've have a OpenGPG smartcard version 2.0 and I would generate digests
stronger than SHA1.

I've added "personal-digest-preferences SHA256" to my gpg.conf file,
but when I sign a message the headers still uses SHA1. If I force with
--digest-algo (which is not recommended according to the doc) to SHA256
it works and I'm able to verify the signature.

I've opened a bug[1], but I was told that it was not a bug.
Then could someone enlighten me about the reasons of this?

Cheers

Laurent Bigonville

[1] https://bugs.g10code.com/gnupg/issue1194