UmbrelOS BIOS LEGACY

I had Umbrel 0.5 running on an old notebook that I installed using the https://umbrel.sh script.

This week I needed to change the SSD and take the opportunity to install the new version of UmbrelOS 1.1.
However, I am unable to install this new version, as my old notebook does not have UEFI, but only Legacy BIOS.
How can I install UmbrelOS on legacy BIOS?