HP ProLiant DL385p Gen8 Server - Manual (Page 45)

Hardware options installation 45
6. If a full-length expansion board is installed in the primary PCIe riser cage, release the full-length
expansion board retainer, and then remove the PCIe riser cage.
7. If a full-length expansion board is installed in the secondary PCIe riser cage, release the full-length
expansion board retainer, and then remove the PCIe riser cage.