Testing new hppa install CD - gpgv still fails

I tried the newest testing install CD on HP A180c. Booted fine from CD.

It still tries to find buster but does not, but can skip to sid - that is OK.

However, it still can not validate gpg siganture on sid, like the previous installer:

Apr 11 13:54:32 main-menu[181]: (process:1305): http://ftp.ports.debian.org/debian-ports/dists/buster/Release:
Apr 11 13:54:32 main-menu[181]: (process:1305): 2019-04-11 13:54:03 ERROR 404: Not Found.
Apr 11 13:54:32 main-menu[181]: (process:1305): 2019-04-11 13:54:32 URL:http://ftp.ports.debian.org/debian-ports//dist
Apr 11 13:54:38 main-menu[181]: INFO: Menu item 'download-installer' selected
Apr 11 13:54:40 anna[1369]: 2019-04-11 13:54:40 URL:http://ftp.ports.debian.org/debian-ports//dists/unstable/Release [
Apr 11 13:54:41 anna[1369]: 2019-04-11 13:54:41 URL:http://ftp.ports.debian.org/debian-ports//dists/unstable/Release.g
Apr 11 13:54:41 net-retriever: gpgv: Signature made Thu Apr 11 07:56:45 2019 UTC
Apr 11 13:54:41 net-retriever:
Apr 11 13:54:41 net-retriever: gpgv:                using RSA key 66571731B5A71F91C501F3FDDA1B2CEA81DCBC61
Apr 11 13:54:41 net-retriever: gpgv: Can't check signature: No public key
Apr 11 13:54:41 net-retriever:
Apr 11 13:54:41 net-retriever: error: Bad signature on /tmp/net-retriever-1373-Release.

Is there any way to add the corresponding APT PGP key manually? There's no gpg nor apt-key in the target yet.