Serial image stick on boot

[emilio.b]

Hello all
i'm new with opnsense.
I'm trying to install the OPNsense-16.1.8-OpenSSL-serial-amd64.img on a miniITX board (Dual Core Intel® Atom™ C2358).

The board has only serial console (no VGA).
I follwed the basic instructions from site and made a usb pendrive with Rufus (dd image).
Then booted the board from the pendrive.

I can see the boot process with serial console (COM1 115200 with putty).
Opnsense boot proceed until it sticks undefinitely with the screenshot i've attacched.

I can see the pendrive activity even if the serial console appears to have nothing to show anymore.
It seems to me that the booting process at a certain point changes the console or switch to vga or something else i'm not aware of.

Please any help would be much appreciated here

TIA