Hello,
add "console=tty1" to l4linux command line. But genode's VESA driver don't work on all hardware. I have tried to run Genode on real hardware and saw display not working on my PC. Monitor has changed resolution and has showed nothing.
I just want to point you to a discussion about this problem at our issue tracker:
https://github.com/genodelabs/genode/issues/417
In the discussion, you can find proposals for possible work-arounds (i.e., using the 'preinit' option of the VESA driver) as well as the outline of a pending solution.
Cheers Norman