I have Windows 10 and Ubuntu 16.04 running on 2 hdd and 1 ssd. 1TB ssd is what I've been dual-booting from, with 500GB for Windows and 500GB for Ubuntu. One other hd is for Win (3TB) and one for Ubuntu (1TB).
After a Windows update, I got the grub rescue screen, but wasn't able to restore the dual-booting status. I've tried several different things, including most in this post with a similar issue. Tried boot-repair several times with no effect. Here is a recent pastebin.
ASRock mobo is currently set to UEFI with options for legacy BIOS for some things. Not sure if this is relevant, but wanted to mention it here. Have not found an EFI file in ubuntu.
Any help greatly appreciated.