DEC740 reinstall 23.1 stuck - interface flapping

[junicast]

Hi,
I need to reinstall OPNsense on my DEC740. For that I downloaded:
OPNsense-23.1-OpenSSL-serial-amd64.img
Flashing it onto USB and then booting from it. So far no problem.
Then it seems to be bringing up the NICs and that's when the Installer gets stuck.

Every minute or so the interface goes Down and Up again, but the installer won't continue. I tried several flash drives -> No change.
I reset the UEFI settings to default -> No change.

Does someone have an idea what's happening here? Should I try an older version of OPNsense?

junicast