Yes, the solution was very simple but I had to look lots of different threads so I´m summarizing here a step by step procedure in order to get a Rasperry PI5 (bookworm 64 bit OS) running HA OS 12.2 inside a virtual manager KVM
1o) install virtual manager:
sudo apt install virt-manager
2o) Download HA OS for arm64bit arquitecture:
This is the link for the 12.2 version, but you can browse github for the version you want:
https://github.com/home-assistant/operating-system/releases/download/12.2/haos_generic-aarch64-12.2.qcow2.xz
NOTE: This is the trick, it is not mentioned in the HA linux installation page. There, implicitily, it assumes that you´re running an intel/amd (x86_64) arquitecture so the qcow2 files provided are for intel not arm arquitecture and the configuration of virtual manager refers just to x86 and x86_64 platforms. It took me 2 days to figure out that.
In othe words DON´T USE the image provided in the HA Linux installation page for Rasperry PI installations, use the link above.
3o) launch virtual machine manager (GUI) and create a machine
Basically select the import disk image option and use all the default options(virt type KVM, architecture aarch64, machine type virt)
Click forward and select the aarch64-12.2.qcow2 that you´ve previously decompressed in a suitable path
selecting generic linux 2022 as the operating system you are installing.
Select the Bridge for networking (beyond the scope of this post, but HA will boot even without networking configured which can show you´ve sucessfully installed in the VM)
You me let the default UEFI firmware but there is a trick. The first time you run the virtual machine it´s not going to boot. It´s going to show “security violation”. This is due the secure boot being enabled and HA does not support that. The workaround is very easy. Just press enter, this will take you to the Firmware setup (When I was young it was called BIOS setup kkkkkk).
There you go to device manager and disable secure boot and restart.
The magic will happen!!, HA OS will boot and after a while the root login will appear. This workaround has to be done just once, the VM persist the new firmware setup. There is an option which is look for a already non-secure boot UEFI firmware for aarch64. It would take me time for that and the workaround takes 30 seconds and done.
That´s it, you got HA installed. It took me some hours to figure out how to setup a bridge and get it used by HA network but I think this is beyond the scope of this post, there are a lot of posts and youtube videos regarding bridges and Debian