Are you sure BKHD version shares a pcie lane between the 2nd m.2 and x1?
The converted itself does not make anything about ASPM. I had one laying around so It was more convenient for me than buying a PCIe version of asm1166 controller.
If you plug an ASM166 into PCIe Port 11 (second m.2) slot with ASPM enabled you will get some AHCI unavailable errors and HHDs not recognized by OS. But it works with PCIe port 9 (x1 port).
The converted itself does not make anything about ASPM. I had one laying around so It was more convenient for me than buying a PCIe version of asm1166 controller.
If you plug an ASM166 into PCIe Port 11 (second m.2) slot with ASPM enabled you will get some AHCI unavailable errors and HHDs not recognized by OS. But it works with PCIe port 9 (x1 port).