Under the current implementation, booting from removable media using
a architecture-specific default image name, say BOOTAA64.EFI, is
supported only in distro_bootcmd script. See the commit 74522c898b35
("efi_loader: Add distro boot script for removable media").
This is, however, half-baked implementation because
1) UEFI specification requires this feature to be implemented as part
of Boot Manager's responsibility:
3 - Boot Manager
3.5.1 Boot via the Simple File Protocol
When booting via the EFI_SIMPLE_FILE_SYSTEM_PROTOCOL, the FilePath will
start with a device path that points to the device that implements the
EFI_SIMPLE_FILE_SYSTEM_PROTOCOL or the EFI_BLOCK_IO_PROTOCOL. The next
part of the FilePath may point to the file name, including
subdirectories, which contain the bootable image. If the file name is
a null device path, the file name must be generated from the rules
defined below.
...
3.5.1.1 Removable Media Boot Behavior
To generate a file name when none is present in the FilePath, the
firmware must append a default file name in the form
\EFI\BOOT\BOOT{machine type short-name}.EFI ...
2) So (1) entails the hehavior that the user's preference of boot media
order should be determined by Boot#### and BootOrder variables.
With this patch, the semantics mentioned above is fully implemented.
For example, if you want to boot the system from USB and SCSI in this
order,
* define Boot0001 which contains only a device path to the USB device
(without any file path/name)
* define Boot0002 which contains only a device path to the SCSI device,
and
* set BootOrder to Boot0001:Boot0002
To avoid build error for sandbox, default file name "BOOTSANDBOX.efi"
is defined even if it is out of scope of UEFI specification.
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
On sandbox use binary name corresponding to host architecture.
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
4e65ca00f3