radxa-repo / bullseye Goto Github PK

'sudo apt update' gives the following error:
Error:9 https://radxa-repo.github.io/apt rockchip-bullseye InRelease
Le seguenti firme non sono state verificate perché la chiave pubblica non è disponibile: NO_PUBKEY 883854C2D3D73467

The second line is in italian because of the localisation of the OS. I try to back translate it to english:
The following signatures weren't verifed because the public key isn't available: NO_PUBKEY 883854C2D3D73467

I omit to copy here the obvious warnigs emitted by 'sudo apt update' in consequence of the former error.