[ubuntu] 24.04 Conflicting values set for option Signed-By after install of boot-repair failed

I tried to install boot-repair, but the installation aborted and told me to install grub-efi and os-prober.

When I tried to install those two, I got this error:

E: Conflicting values set for option Signed-By regarding source https://ppa.launchpadcontent.net/yan...repair/ubuntu/ noble: /etc/apt/keyrings/boot-repair.gpg != -----BEGIN PGP PUBLIC KEY BLOCK-----

$ sudo apt-get install -y grub-efi os-prober
E: Conflicting values set for option Signed-By regarding source https://ppa.launchpadcontent.net/yan...repair/ubuntu/ noble: /etc/apt/keyrings/boot-repair.gpg != -----BEGIN PGP PUBLIC KEY BLOCK-----
mQINBGYzoxcBEACurKKBm4hHDCA ...

followed by the rest of the key block

-----END PGP PUBLIC KEY BLOCK-----

E: The list of sources could not be read.

sudo apt update
gives the same error

What can I do?