[Request] Gigabyte GA-890GPA-UD3H rev2 BIOS with NVMe support

No, according to my knowledge the only NVMe SSD, which is bootable in LEGACY mode, is the Samsung 950 Pro.
If you want to boot off another NVMe SSD model, you may have to modify the mainboard BIOS by inserting a customized NVMe Option ROM. For details look >here<.