8.5.9.1 Boot Operation Mode

In Boot Operation mode, the processor can read boot data from the e.MMC device by keeping the CMD line low after power-on before issuing the CMD1. The data can be read from either one of the boot partitions or the user area according to BOOT_PARTITION_ENABLE in the Extended CSD register (see “Embedded MultiMedia Card (e.MMC) Electrical Standard 4.51” ).