The PMC_MIO Bank 1 is expected to be at 1.8V for SD v3.0 boot modes. In SD v3.0 boot modes, an external voltage level translator is needed to enable the controller to initially interface at 3.3V for SD card and optionally switch to 1.8V devices for high-speed transfers.
Figure 1.
SD Flash
Interface v 3.0 Diagram with Voltage Level Translator
