Does somebody know how to get nvme ssd drives bootable on older Intel Motherboard how don't have a Slot for this? I have installed an PCI-e Adapter with the drive. I can install Windows on this drive but i can't boot from this because the bios don't recognize them. UFI Bios are modular, so i should be possible to add an Driver or?
The concept of NVMe drives simply did not exist when the last set of Intel Desktop Boards (i.e. the 8 Series boards supporting the (Haswell) 4th generation Intel Core processors) were launched and thus there is no support for NVMe included in their BIOS. Subsequent to this set of boards being launched, Intel exited from the Desktop Boards business and thus no additional capabilities were ever developed (that included not only NVMe but also the lack of support for the Haswell Refresh processors).
It is theoretically possible that a PCIe adapter like that described could include an OpROM that provides a UEFI BIOS Driver that supports booting from attached NVMe drives. I have never seen such an adapter, however.