Can't install NetBSD to ffs2 partition, no errors

[Ottavio Caruso <ottavio2006-usenet2012%yahoo.com@localhost>]

Hi,

1) I have dd'ed the UEFI usb image of NetBSD 9.3/amd64 to a USB drive
and booted  from it.

2) From the utility menu, I have created a FFSv2 partition from 35GB
unused space
https://i.ibb.co/XxVy1M9/gpt-show-wd0.jpg
https://i.ibb.co/4sSCXmw/partition-manager.jpg

3) Then I went back into the install menu:
https://i.ibb.co/JCBX1p1/prompt-1.jpg

4) Accepted the warning to make changes on disk:
https://i.ibb.co/6Pzvmvw/prompt-2.jpg

5) Selected NetBSD (dk6@wd0)

6) The menu goes back to point 3 without any apparent errors.

I would have expected the menu would offer to create a disklabel from
there, but it didn't.

No apparent warnings in dmesg.

Any hint?