Vitek,
Thank you for the respons! I do want Sophos UTM indeed, no XG.
As you said serial console is enabled by default now, then the problem is 90% the USB stick. I already doubted if that was prepared well. On my MacOS I tried:
# sudo dd bs=1m if=/Users/xxx/asg-9.509-3.1.iso of=/dev/disk4
Did not give any error, but stick is not booting. Already tried different stick (old and new ones). I will give it another try, but maybe you have some advice? ;-)
kind regards,
Oscar