I own Acer S1002 "laptop". Its one of those 2 in 1 tableto-laptop devices running on Atom CPU. It will only install Windows in 32 bit version because it has a dumb**s 32 bit EFI bootloader.
When installing ElementaryOS 5.1 everything (almost) is peachy. It installs it boots - few minor issues.
When installing ElementaryOS 6 it installs but after a reboot I get an EFI shell.
Upon closer look the EFI partition on 5 contains:
While ElementaryOS 6 only shows 64 bit files.
I tried copying files listed above to the EFI partition of the ElementaryOS 6 installation - that did not fix anything.
Machine's bios does not allow to disable UEFI / enable legacy boot.
Chrooting into installation and installing refind does not help...
Tell me Gandalf, what I must do now?
Please do not leave me with Windows 10 32 bits as my only option :)
Solution below. Warning, beyond here there be dragons.
Ok I am sorted... I will show you how but do so at your own risk. You need to know at least basics and I am not taking any responsibility if you fubar...
First what I did was I've installed ElementaryOS 6 and rebooted.
I rebooted into ElementaryOS 6 LiveUSB.
Next I've followed a prompt and went into the "Demo" mode.
In demo mode I've connected to wireless.
Then I've opened a terminal and ran:
sudo su mount /dev/mmcblk1p4 /mnt
(mmcblk1p4 is my /)
mount -t proc none /mnt/proc/ mount -o bind /dev /mnt/dev/ mount -o bind /sys /mnt/sys/ mount -o bind /run /mnt/run/ mount /dev/mmcblk1p1 /mnt/boot/
(mmcblk1p1 is my /boot)
mount /dev/mmcblk1p2 /mnt/boot/efi/
(mmcblk1p2 is my /boot/efi)
chroot /mnt apt update && apt upgrade && apt dist-upgrade && apt autoremove
(ignore messages about not being able to write the log)
apt install efibootmgr grub-common grub-efi-ia32 grub-efi-ia32-bin grub-pc-bin grub2-common mokutil secureboot-db
(You will be asked to type in a phrase to continue the installation)
apt autoremove grub-install /dev/mmcblk2 update-grub exit reboot
After reboot I was finally able to boot :)