Add a description of the EFI variables needed to match a Boot#### entry with an initrd.
Signed-off-by: Ilias Apalodimas <ilias.apalodi...@linaro.org> --- doc/uefi/uefi.rst | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/doc/uefi/uefi.rst b/doc/uefi/uefi.rst index dc930d924022..d8b083ffa708 100644 --- a/doc/uefi/uefi.rst +++ b/doc/uefi/uefi.rst @@ -229,6 +229,21 @@ UEFI variables. Booting according to these variables is possible via:: As of U-Boot v2020.10 UEFI variables cannot be set at runtime. The U-Boot command 'efidebug' can be used to set the variables. +Initrd with the boot manager +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Kernel versions >= 5.6 can use EFI_LOAD_FILE2_PROTOCOL to load an initramfs. +When U-Boot is configured with CONFIG_EFI_LOAD_FILE2_INITRD=y the boot manager +will install the protocol, if an EFI variable matching the BootCurrent value +is found and contains a valid file path. The EFI variable name is 'Initrd####' +and the file path format is '<device> <partition> <filename>'. + +This allows users to pair a kernel with a specific initramfs. + +Example: +Boot0010 will search for Initrd0010 and try to install the protocol with +the file path specified in Initrd0010. + Executing the built in hello world application ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- 2.30.0
