Then I don't know why it does not work, and I would assume this combination of SBC and NVME just won't work. Such cases exists, although frustrating that is does not work. You could cross check, but I don't know it you have other brands NVME to try with the OPi5 Ultra. I would also be not surprised if there is simply something wrong of missing in the U-Boot or DTB (all versions, even the one from manufacturer/xunlong). You can look at versions history of U-Boot for example, just to see how much