The new version u-boot of namepcT4 doesn't seem to be able to boot from nvme.
https://forum.pine64.org/showthread.php?tid=8685
https://github.com/sigmaris/u-boot/
Sigmaris seems to have done quite a lot of work and conducted some tests on pine64. Maybe it should enable these features that are not incorporated into the mainline for other rk3399 devices.