As a quick summary: - Press space during boot, and a boot menu appears with options for any attached boot media with a valid OS (NVMe, USB, microSD, eMMC, ne

As a quick summary: - Press space during boot, and a boot menu appears with options for any attached boot media with a valid OS (NVMe, USB, microSD, eMMC, network) - Press shift during boot, and Raspberry Pi Imager will download over the network and allow you to install an OS onto any valid boot media. - raspi-config has an option to always show the boot selection menu on startup