The Problem
grub-rpi3.efi is built on RPI3 image build stage, and it is missing a crucial module for password prompt:
# efibootmgr -v -v Could not read variable 'BootNext': No such file or directory error trace: vars.c:332 vars_get_variable(): open(/sys/firmware/efi/vars/BootNext-8be4df61-93ca-11d2-aa0d-00e098032b8c/raw_var, O_RDONLY) failed: No such file or directory lib.c:139 efi_get_variable(): ops->get_variable failed: No such file or directory Could not read variable 'BootCurrent': No such file or directory error trace: vars.c:332 vars_get_variable(): open(/sys/firmware/efi/vars/BootCurrent-8be4df61-93ca-11d2-aa0d-00e098032b8c/raw_var, O_RDONLY) failed: No such file or directory lib.c:139 efi_get_variable(): ops->get_variable failed: No such file or directory Could not read variable 'Timeout': No such file or directory error trace: vars.c:332 vars_get_variable(): open(/sys/firmware/efi/vars/Timeout-8be4df61-93ca-11d2-aa0d-00e098032b8c/raw_var, O_RDONLY) failed: No such file or directory lib.c:139 efi_get_variable(): ops->get_variable failed: No such file or directory Could not read variable 'BootOrder': No such file or directory error trace: vars.c:332 vars_get_variable(): open(/sys/firmware/efi/vars/BootOrder-8be4df61-93ca-11d2-aa0d-00e098032b8c/raw_var, O_RDONLY) failed: No such file or directory lib.c:139 efi_get_variable(): ops->get_variable failed: No such file or directory efibootmgr.c:372 read_order(): efi_get_variable failed: No such file or directory No BootOrder is set; firmware will attempt recovery Could not read variable 'MirrorCurrent': No such file or directory error trace: vars.c:332 vars_get_variable(): open(/sys/firmware/efi/vars/MirrorCurrent-7b9be2e0-e28a-4197-ad3e-32f062f9462c/raw_var, O_RDONLY) failed: No such file or directory lib.c:139 efi_get_variable(): ops->get_variable failed: No such file or directory Could not read variable 'MirrorRequest': No such file or directory error trace: vars.c:332 vars_get_variable(): open(/sys/firmware/efi/vars/MirrorRequest-7b9be2e0-e28a-4197-ad3e-32f062f9462c/raw_var, O_RDONLY) failed: No such file or directory lib.c:139 efi_get_variable(): ops->get_variable failed: No such file or directory
The Solution
Follow the steps outlined below to fix the issue:
1. Verify that file is in place:
# file grub-rpi3.efi
2. Install package grub2-efi-aa64-modules.
3. Set the default boot device:
# echo "set root=(hd0,msdos2)" > grub2-early.cfg
4. Review grub-early.cfg to verify there is exactly one “set root” string.
5. Build the image:
# grub2-mkimage -c grub-early.cfg -O arm64-efi -o grub-rpi3.efi -p "(hd0,msdos1)/efi/redhat" all_video boot btrfs cat chain echo efifwsetup efinet ext2 fat font gfxmenu gfxterm gzio halt hfsplus iso9660 jpeg loadenv loopback lvm mdraid09 mdraid1x minicmd normal part_apple part_msdos part_gpt password_pbkdf2 png reboot regexp search search_fs_uuid search_fs_file search_label serial sleep syslinuxcfg test tftp video xfs http linux configfile
6. Verify the new file in the local directory:
# file grub-rpi3.efi
7. Add a copy of the file to /boot/efi/EFI/redhat/ directory.
# cp grub-rpi3.efi /boot/efi/EFI/redhat/
This should also produce a warning about replacing an existing file.
8. Flush the I/O buffers out to media:
# sync; sync; sync
9. Gracefully reboot.