Comment 71 for bug 1766945

I got bit.

I attempted a new install of the latest (as of 2021-08-01) 18.04 (5.xx kernel as I recall) onto a 19GB partition (/dev/sdf2) on one disk while specifying the bootloader location be onto a different disk (/dev/sda) with an existing, working, boot-efi partition (/dev/sda1).

I had done this same os install successfully onto a 7GB partition on a 3rd disk (/dev/sdc2) just before.

On the 19GB install, a fatal error occurred suggesting it was unable to write to do the final grub install onto /dev/sda.