20.10 grub-install failure

[Zoltan The G]

Once again trying to build my multi-boot flash drives and external SSDs with the latest Ubuntu.

Contents of the ISO to a FAT32-formatted flash drive. Boot in UEFI mode and install grub to allow also booting in legacy mode. 20.04 works. 20.10 fails. Test machine: ThinkPad X1 Yoga Gen 5.

20.04:

ubuntu@ubuntu:~$ sudo su
root@ubuntu:/home/ubuntu# mount -o remount rw /cdrom
root@ubuntu:/home/ubuntu# grub-install --force --no-floppy --boot-directory=/cdrom/boot /dev/sda
Installing for i386-pc platform.
Installation finished. No error reported.
root@ubuntu:/home/ubuntu#

20.10:

ubuntu@ubuntu:~$ sudo su
root@ubuntu:/home/ubuntu# mount -o remount rw /cdrom
root@ubuntu:/home/ubuntu# grub-install --force --no-floppy --boot-directory=/cdrom/boot /dev/sda
Installing for x86_64-efi platform.
grub-install: error: cannot find EFI directory.
root@ubuntu:/home/ubuntu#

I realize that live boot isn't a priority other than compatibility testing and installation but this constant breakage (persistence, looped ISO booting...) makes my intended use impossible. Multiboot external drives with Ubuntu as the base distro are very useful for recovery and forensics - when they work...

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1902557/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Zoltan The G (wdw)]

Adding grub-installer as package. Did that originally but it disappeared and got a nag from the bot...

[Zoltan The G (wdw)]

Well duh, it was right there in black and white: it's defaulting to an efi install. That's new.

Fix is adding --target=i386-pc to the install command.

Now if I could just get persistence to work...