I followed https://wiki.postmarketos.org/wiki/Fairphone_5_(fairphone-fp5)#Manual_install "SD memory card", with https://images.postmarketos.org/bpo/v26.06/fairphone-fp5/plasma-mobile/20260619-0151/ : "Waiting for root partition" then it lands on a CLI.

In general, except the Pinephone & Pro, booting a microSD card worked?