Dual Boot Windows License

Hello

I want to buy a new license for Avast Ultimate, and currently I have a dual boot Windows in the same computer.

Do I need to buy a multidevice license (10 devices, 5 devices, etc…), or can I buy a single device license for both dual boot windows?

I tried searching, but didn’t find any recent info if my computer can be considered 1 device or 2 devices

Thanks. Regards