Unfortunately, my boot drive is finally dead yesterday, so I was unable to boot up despite the OS itself being good.
Here are few steps I did:
- remove the dead disk 0. (with disk 0 connect, my BIOS would stuck at POST)
- boot into ubuntu live CD, use GParted to move the OS partition and make a room of 500MiB before it
- Create the EFI partition. it is just a FAT32 partition with boot label.
- use a windows 10 installation media, hit shift+F10 to enter cmd, then use
to create the bootloader
- For whatever reason, now I can see the bootloader, but it somehow won't get me into windows 10. So now I used the windows 10 installation media's repair tool, and it automatically repaired it. (note I tried using this step before everything else, but it won't work until I create the EFI partition manually)