I'm trying to install elementary OS on raid0. My ESP, of course, is not part of the raid, but rather a separate partition near the beginning of one of the disks. I boot into the live ISO, download mdadm, then assemble my raid (raid0 striped across four nvmes). The install goes great and system files get downloaded and copied onto the raid just fine. However, things take a bad turn when grub tries to install the bootloader on ESP. Here is output from the install journal. As you might guess, boot partition is on /dev/nvme1n1p1 and root is on /dev/md125.
Jun 14 00:14:29 elementary grub-installer: info: grub-install does not support --no-floppy
Jun 14 00:14:29 elementary grub-installer: info: Running chroot /target grub-install --force "/dev/nvme1n1p1"
Jun 14 00:14:29 elementary grub-installer: Installing for x86_64-efi platform.
Jun 14 00:14:30 elementary grub-installer: grub-install: error: disk `md125' not found.
Jun 14 00:14:30 elementary grub-installer: error: Running 'grub-install --force "/dev/nvme1n1p1"' failed.
Jun 14 00:14:32 elementary nm-applet[27236]: gtk_widget_destroy: assertion 'GTK_IS_WIDGET (widget)' failed
Jun 14 00:14:32 elementary nm-applet[27236]: gtk_widget_destroy: assertion 'GTK_IS_WIDGET (widget)' failed
Jun 14 00:14:32 elementary nm-applet[27236]: Can't set a parent on widget which has a parent
Jun 14 00:14:43 elementary ubiquity[29013]: Reverting lockdown of the desktop environment.
Jun 14 00:14:43 elementary activate-dmraid: No Serial ATA RAID disks detected```