Hmm, I am using MBR, I will try changing to GPT.
/boot is FAT32
/ is ext4 with Manjaro minimal
I have successfully used both external SD and USB flash drives. (Due to my case, I can not access the RPI SD drive)
I boot the Manjaro minimal image and remove all files (except for kernel and initramfs) from /boot.
Then I place this uefi firmware in /boot and copy other kernels and initramfs.
Then I install grub2 and make the grub image with --removable, it recognizes aarch64 without passing a parameter and places the bootaa64.efi in /boot/EFI/BOOT/
When it boots, it does not load the grub.cfg. I think may be due to how I made the grub image? It boots to a grub prompt, so I then run configfile (hd0,msdos1)/grub/grub.cfg
This simple grub.cfg menu:
menuentry "Ubuntu boot" {
echo "Ubuntu booting..."
linux (hd0,msdos1)/kernel6.img.sav root=/dev/sda2 rw rootwait console=serial0,115200 console=tty1 selinux=0 plymouth.enable=0 smsc95xx.turbo_mode=N dwc_otg.lpm_enable=0 kgdboc=serial0,115200 usbhid.mousepoll=8 audit=0
initrd (hd0,msdos1)/initramfs-linux6.img.sav
boot
}
menuentry "VIM3 boot" {
echo "VIM3 booting..."
linux (hd0,msdos1)/kernel7.img.sav root=/dev/sda2 rw rootwait console=serial0,115200 console=tty1 selinux=0 plymouth.enable=0 smsc95xx.turbo_mode=N dwc_otg.lpm_enable=0 kgdboc=serial0,115200 usbhid.mousepoll=8 audit=0
initrd (hd0,msdos1)/initramfs-linux7.img.sav
boot
}
menuentry "Manjaro boot" {
echo "Manjaro booting..."
linux (hd0,msdos1)/kernel8.img.sav root=/dev/sda2 rw rootwait console=serial0,115200 console=tty1 selinux=0 plymouth.enable=0 smsc95xx.turbo_mode=N dwc_otg.lpm_enable=0 kgdboc=serial0,115200 usbhid.mousepoll=8 audit=0
initrd (hd0,msdos1)/initramfs-linux8.img.sav
boot
}
menuentry "Tumbleweed boot" {
echo "Tumbleweed booting..."
linux (hd0,msdos1)/kernel9.img.sav root=/dev/sda2 rw rootwait console=serial0,115200 console=tty1 selinux=0 plymouth.enable=0 smsc95xx.turbo_mode=N dwc_otg.lpm_enable=0 kgdboc=serial0,115200 usbhid.mousepoll=8 audit=0
initrd (hd0,msdos1)/initramfs-linux9.img.sav
boot
}
menuentry "System shutdown" {
echo "System shutting down..."
halt
}
menuentry "System restart" {
echo "System rebooting..."
reboot
}
The tumbleweed kernel and initramfs I copied from their rpi4 image and it boots. So far other kernels do not. They freeze after the EFI stub loads the kernel (see post 425 above). The VIM3 kernel does produce some disk activity, however it never progresses.