Sorry...But when you reported 'Grub rescue' error you was not using MBR. Was not this error occur in 4TB GPT Disk ?
Yes, "Grub Rescue" was on GPT disk only, but on the same screen the first line was "Welcome to AIO BOOT", doesn't that mean, AIO is booting? I thought Wonko was talking about the "Grub with blinking cursor" case, it was with mbr disk on BIOS system.
This is the screenshot of GPT 4TB Hard disk: https://www.flickr.c...eposted-public/