Dear Maintainer,I confirm this issue. After upgrade to Debian 10.10 (including a new version shim-signed), Secure Boot no longer works.
I proceeded as usual : - I added my key via command # mokutil --import my-key.der - I rebooted - I obtained shim screen to propose enroll my key. It's done But, after boot, list of enrolled key is empty. # mokutil --list-enrolled MokListRT is empty -- Best Regards, Lilian BENOIT