Comment 29 for bug 2036730

Here is a working armhf command to manually boot a noble-armhf image:

```
qemu-system-arm \
-machine virt -m 3G -smp 2 -cpu cortex-a15 -nographic \
-object rng-random,filename=/dev/urandom,id=rng0 \
-device virtio-rng-pci,rng=rng0,id=rng-device0 \
-drive if=pflash,format=raw,unit=0,read-only=on,file=/usr/share/AAVMF/AAVMF32_CODE.fd \
-device virtio-net-pci,netdev=eth0 \
-netdev user,id=eth0,hostfwd=tcp::8022-:22 \
-drive file=autopkgtest-noble-armhf.img,if=virtio,format=qcow2
```

The main takeaways are:
* use of `qemu-system-arm`, not `qemu-system-aarch64`
* no more than 3G, as there currently is a firmware bug preventing the use of more memory
* `-smp 1` is not supported, be sure to give at least two cores

I'll now see about patching autopkgtest to craft that kind of commandline when calling `qemu` with `armhf`.