Hi Vishal,
just as a shot in the dark, the problem may be related to the NIC driver. The l4linux.run scenario expects an e1000 ethernet card to be present. Maybe your machine lacks such a device? For a quick test, I just tried starting the l4linux.iso image on Qemu while omitting the network-related arguments and observed the effect that you reported (only a lonely penguin who looks desperately for a command-line prompt).
You could try to remove the NIC driver from your setup. Just comment-out the following lines in 'ports-foc/run/l4linux.run'
#append_if [have_spec x86] config { # <start name="nic_drv"> # <resource name="RAM" quantum="2M"/> # <provides><service name="Nic"/></provides> # </start>}
Of course, this change will make the automated test ('make run/l4linux') fail since no network will be available anymore. But you can give the resulting ISO image ('var/run/l4linux.iso') a try on your PC hardware and see if you get to see the prompt.
Still, I second Stefan's suggestion about making the output of the serial console available.
Cheers Norman