5960 - Platform Manager 2 / XO3D: How to get the ASC-10 Dual Boot Document for XO3D?
Please refer to AN6095 Adding Scalable Power and Thermal Management to ECP5 in the section on Dual Boot (multi-boot is mentioned) and FPGA-TN-02039 for ECP5 sysCON-FIG Usage Guide for additional details on multi-boot.