Hi @Ohsnaps,
Thanks for your reply. I have two gpus installed and linked with nvlink and set sli. Before the flashback, I can enter to windows, the system took about 2 mins to reach window login screen. When I tried to boot to uefi via recovery setting, the uefi section can not be showed, then later just it was to windows login section. It might be as you mention the bios might be loaded on the other one. But now after I did the flashback, I can not boot to the system complete, it seems that there is no any video output and reading the system on the ssd.