Please be aware of an issue with the PicoZed SOM. This issue was discovered in relation to running the eMMC in High Speed Mode. As of now, we only support Standard Speed Mode eMMC operation. For more information please see the errata documents "PicoZed 7015/7030 Rev C Errata 1.3" / "PicoZed 7010/7020 Rev C Errata 1.0"
and the following forum post as well.