We have an i.mx6 board which is based on mx6sabresd kit. We can download u-boot with USB loader.
and I modified u-boot to detect and run SD card for 4 bit interface.
Our SD card is micro 4 bit wide SD and its card detect pin is also different (CD/DATA3) from origininal kit design. For the small PCB sizes, there is no boot config switches or resistors also. Therefore we will program the fuses to processor to boot from SD card, (or (Q)SPI flash).
I wonder if mx6 boot loader firmware checks for special sd card detect pins and/or if not find a card, does it check CD/DATA3 pins status for u-boot code? do we need any pull up/pull down resistor for this pin to be detected?
Could Anybody help?
Thanks and best regards.