On Thu, Nov 16, 2023 at 6:15 PM Heinrich Schuchardt <heinrich.schucha...@canonical.com> wrote: > > On 11/16/23 17:52, Shantur Rathore wrote: > > Hi Simon, > > > > Currently bootstd - bootmethod_efi only looks for the default > > bootxx64.efi in /EFI/boot folder only. > > Generally many distros end up putting their bootloaders in > > EFI/<distro> folders like EFI/ubuntu and EFI/debian etc. > > > > In x86 worlds, the NVRAM is modified and new boot entries are added to > > support these but in the U-boot world the NVRAM variables are > > read-only. > > I guess you are referring to UEFI boot options. These typically are not > stored in non-volatile RAM but on a SPI flash device. >
Thanks for correcting me. > > > > What would be the best way to implement this? > > > > I was thinking of having a "efi_prefixes" environment variable which > > can be set to "ubuntu debian centos" etc and bootmethod_efi can try > > all of them. Will bootmethod_efi be able to support multiple entries ( > > thinking of multiboot ) ? > > On my laptop I have: > > EFI/Microsoft/Boot/bootmgr.efi > EFI/Microsoft/Boot/memtest.efi > EFI/Boot/bootx64.efi > EFI/Boot/fbx64.efi > EFI/Boot/mmx64.efi > EFI/debian/shimx64.efi > EFI/debian/grubx64.efi > EFI/debian/mmx64.efi > EFI/debian/fbx64.efi > EFI/ubuntu/grubx64.efi > EFI/ubuntu/shimx64.efi > EFI/ubuntu/mmx64.efi > > Obviously each installed operating system provides multiple EFI binaries > and non uses the fallback file name BOOT<ARCH>.EFI. A value "ubuntu > debian centos" would not be able to describe which file you are looking > for. > > We already have the U-Boot command line eficonfig and efidebug commands > to set up UEFI boot options which can describe which EFI binary to load > and which command line to pass to it. These are considered by the > existing boot flows. So, I am building a new RockPro64 based cluster and using Canonical MAAS to set them up automatically, booting them up using DHCP and installing them over the network. I configured an Armbian image using Packer to be compatible with MAAS and it happily installs it. As part of installation process, a grub-install is run which installs the grub efi, this EFI ends up in EFI/debian instead of expected EFI/boot. To be able to make it boot, I have to add commands to move it to EFI/boot. I am trying to find a way in U-Boot that would allow me to skip this step. With eficonfig if I understand correctly, it would need manual intervention to create boot entries. > > If you are installing the shim-signed package on Ubuntu, the EFI boot > option for Ubuntu is set up by EFI/BOOT/BOOT<ARCH>.EFI using the content > of EFI/ubuntu/BOOT<ARCH>.CSV. This is done before ExitBootServices() and > therefore should work with current U-Boot. > > Patches are pending upstream to make EFI variables writable from Linux > if they are stored in the RPMB partition in the eMMC. See this series: > > https://lore.kernel.org/linux-efi/20231107054057.1893-2-masahisa.koj...@linaro.org/ > Would it be possible to save it in SPI Flash as the U-Boot environment ? Kind regards, Shantur > Best regards > > Heinrich
