PhantomOS won't boot on Linux, QEMU

[kolayne]

I am using

QEMU emulator version 4.2.1 (Debian 1:4.2-3ubuntu6.18)
Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers

(is there any other version that I should try?)

I have not succeeded in running the run/phantom.sh script (it seems like it has not worked in the last couple of years... I could make a PR later), so I run the following commands in the terminal (work directory is run):

qemu-img create -f qcow2 phantom.img 5G
qemu-system-x86_64 -smp 3 -vga vmware -s     -serial file:serial0.log -boot a -no-fd-bootchk -fda img/grubfloppy.img -hda fat:rw:fat -hdb phantom.img   -net nic,model=rtl8139 -net user -enable-kvm`

After that a QEMU window opens, showing some output from BIOS (see the screenshot), printing the string <sleep> on newline once per a couple of (~30?) seconds, consuming 100% of one CPU core. This lasts for several (10-15?) minutes, after which the CPU consumption stops, and the QEMU window's content gets replaced with a grub console.

Is there anything I am doing wrong? How can I run the project?