This adapter will not work with U.2 drive due to on-board PCIe PERST# buffer is being reversed (check the schematics I traced from this board). Because of that, reset from U.2 drive is being driven *to* the motherboard, which will prevent it from correct start-up and showing BIOS. After swapping R5 and R6 (that essentially omitted the reset buffer circuit) my issue was solved. Seller was quite nice and offered me to send another board (with R4) installed, but I don't think it will solve this issue.
This adapter will not work with U.2 drive due to on-board PCIe PERST# buffer is being reversed (check the schematics I traced from this board). Because of that, reset from U.2 drive is being driven *to* the motherboard, which will prevent it from correct start-up and showing BIOS. After swapping R5 and R6 (that essentially omitted the reset buffer circuit) my issue was solved. Seller was quite nice and offered me to send another board (with R4) installed, but I don't think it will solve this issue.