To enable dual boot on a T2 equipped Mac, one needs to change some Security settings first.

T2 Security Settings


BIAB 2023 Audiophile, 24/60 Core M2 Mac Studio Ultra/8TB/192GB Sonoma, M1 MBAir, 2012 MBP
Digital Performer 11, LogicPro
Finale27.4, Dorico5, Encore5, SmartScorePro64, Notion6, Overture5