When you remove a PCIe ExpressModule (EM) card and replace it by hotplugging a card of a different type, the OS might not be able to configure the new card. This is because before booting to the OS, the BIOS allocates resources based on the card's requirements during POST. If the new card requires more resources than the original, the OS does not have the ability to allocate more resources to the new card at this time, and the card does not operate correctly.
Workaround 1
Hotplug PCIe EM cards in previously empty slots.
Workaround 2
If a hotplugged PCIe EM card fails to operate correctly, reboot the server.