Description of problem:

With RHEL9, the /boot/efi/EFI/redhat/grub.cfg file is now a wrapper redirecting to unified configuration file /boot/grub2/grub.cfg.
It appears that the wrapper can fail to find /boot partition (or / if /boot and / are merged). This especially happens if /boot/efi is on its own disk (e.g. /dev/vda) while the rest is on another disk (e.g. /dev/vdb).

The root cause is EFI firmware didn't plumb all disks, but only the one hosting /boot/efi.

This happens at least with VMWare at hardware level 19 and QEMU/KVM (Fedora 37).

The solution is to add the following stanza before searching for the device:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
connectefi scsi
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

Version-Release number of selected component (if applicable):

grub2-common-2.06-46.el9.noarch and later

How reproducible:

Always

Steps to Reproduce:
1. Create a QEMU/KVM VM with 2 disks

vda: 1GB, which will host /boot/efi
vdb: 10GB, which will host the rest

2. Install the system making sure /boot/efi is on vda and the rest on vdb
3. Poweroff the system once installation complete (don't just reboot)

4. Boot the system on disk

Actual results:

Grub prompt

Expected results:

System boots

Additional info:

At Grub prompt we can see only vda is connected, preventing /boot from being found:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
grub> ls
(proc) (hd0) (hd0,gpt1)

grub> cat /efi/redhat/grub.cfg
grub> cat /efi/redhat/grub.cfg
search --no-floppy --fs-uuid --set=dev f2ed30fe-ff8d-44bc-9b06-342f4f31f6b1
set prefix=($dev)/grub2

export $prefix
configfile $prefix/grub.cfg

grub> search --no-floppy --fs-uuid --set=dev f2ed30fe-ff8d-44bc-9b06-342f4f31f6b1
error: ../../grub-core/commands/search.c:315:no such device: f2ed30fe-ff8d-44bc-9b06-342f4f31f6b1.
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

After executing "connectefi scsi", the partition is found:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
grub> connectefi scsi
grub> ls
(proc) (hd0) (hd0,gpt1) (hd1) (hd1,gpt2) (hd1,gpt1) (cd0) (cd0,msdos2) (lvm/rhel-swap) (lvm/rhel-root)
grub> search --no-floppy --fs-uuid --set=dev f2ed30fe-ff8d-44bc-9b06-342f4f31f6b1
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------