The location to install grub to only applies to bios grub. For EFI, that setting is ignored and grub must be installed to /boot/efi. Did you configure the ESP on the other drive to be mounted in /boot/efi?
I suppose that drop down should be hidden when using EFI mode. ** Changed in: ubiquity (Ubuntu) Importance: Undecided => Low ** Changed in: ubiquity (Ubuntu) Status: New => Triaged ** Summary changed: - wrong EFI partition modified + "Install grub to" drop down should be hiddden in EFI mode ** Summary changed: - "Install grub to" drop down should be hiddden in EFI mode + "Install grub to" drop down should be hidden in EFI mode -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1366264 Title: "Install grub to" drop down should be hidden in EFI mode To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1366264/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs