Windows 10: A required device isn't connected or can't be accessed. 0xc000000e

Installed windows 10 on a new SSD but I apparently made the mistake of doing this while the original windows 10 HDD was still connected. Apparently the windows 10 installer edits the EFI of the original drive, which is definitely not wanted. Anyway, this causes the original windows 10 installation, on the original drive, to fail to boot because the EFI now points to a drive that doesn't exist. How can the EFI on the original drive be updated to correct this?

After messing around for a day or two I found out that none of the bootrec commands posted everywhere worked. For example:

bootrec /fixboot
The system cannot find the file specified.

The solution was to use "EasyUEFI" by "Hasleo Software" to edit the EFI to point to the actual windows installation. Took all of 2 seconds to fix after that.