Disco ubiquity crash

[oldfred]

Installing latest version as of Feb 15, 2019.

I have multiple installs, so using Something Else install option.
I am able to change partition to use to my sdb8 which is previous Disco install.
I tell it not to use swaps that I still have on sda & sdc.

But I want to install grub to sdb's ESP. It recognizes sdb's ESP as the efi partition, but when I try to tell it not to use sda1, my ESP/efi partition it totally locks up with a white box centered on screen with smaller circle with an X in middle and ????? on two lines next to circle with X in white box.

System totally locked up, so logs not available.

Testing to see if any of these related bugs are fixed in grub.
Ubuntu Installer uses wrong bootloader location for USB/sdb UEFI installs
https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1173457
https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1396379
https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1229488
https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1229488

[oldfred (oldfred)]

Rebooted and reinstalled.
Using different order for selecting ESP/efi partition it worked without error on not using sda, but installed to ESP on sda.
Install log showed this:

Feb 15 20:23:36 ubuntu grub-installer: info: Installing grub on '/dev/sdb'
Feb 15 20:23:36 ubuntu grub-installer: info: grub-install does not support --no-floppy
Feb 15 20:23:36 ubuntu grub-installer: info: Running chroot /target grub-install --force "/dev/sdb"
Feb 15 20:23:36 ubuntu grub-installer: Installing for x86_64-efi platform.