Unable to select sata drive through PCIe as boot option

Hi everyone,

i recently got my ZimaBlade and i’m currently under testing of the setup which i would like to build for my personal NAS.

My setup is almost composed by:

  • 2x 4TB WD Red Plus (for storage, backups etc)
  • 2x 500GB 870EVO (for OS, VMs and LXCs)
  • 2x 1TB WD Blue (for additional storage)

To extend sata ports i both this PCIe card from amazon and i connected the 2 SSDs and the two WDBlue HDDs to it with an external 5V power supply. The 2 WDRed instead are directly powered from and connected to the ZimaBlade. Everything is detected correctly and from casaos i can view all the drives connected.

The problem comes when i try to select the drives connected to the pcie card as boot option since they are not detected from bios and even from grub installed on the on-board eMMC. With an external USB drive, instes, i was able to install proxmox on the 2 SSDs in ZFS RAID1 without any problem. Am i missing some configuration in the bios?