[U-Boot] [PATCH 01/11] imx: Add bootcmd to load and run UEFI from mmc

[Trent Piepho]

On Mon, 2018-07-16 at 22:28 +0000, Henry Beberman wrote:
> Hi Trent,
> 
> > -----Original Message-----
> > From: Trent Piepho <tpiepho at impinj.com>
> > Sent: Monday, July 16, 2018 10:17 AM
> > To: Henry Beberman <Henry.Beberman at microsoft.com>; u-
> > boot at lists.denx.de
> > Cc: trini at konsulko.com; fabio.estevam at nxp.com
> > Subject: Re: [U-Boot] [PATCH 01/11] imx: Add bootcmd to load and run UEFI
> > from mmc
> > 
> > On Sat, 2018-07-14 at 00:11 +0000, Henry Beberman wrote:
> > > From: Henry Beberman <henry.beberman at microsoft.com>
> > > 
> > > This patch enables i.MX platforms to easily add a boot script to their
> > > U-Boot Proper environment to automatically load and execute an EFI
> > > firmware from the first FAT partition of an MMC device.
> > 
> > Is there a reason to force the first partition instead of using the EFI partition
> > code to select which partition to boot?
> > 
> > I also wonder, on a Linux system, is there a reason the EFI partition must use
> > FAT?
> 
> I need to revise the commit message for this patch. The script is not fixed to the first partition of the selected MMC, it scans the disk for partitions marked bootable, then checks each one of those until it finds the imxboard_efi.fd binary.

That is indeed very different from first FAT partition.  Does bootable
only apply legacy MBR partition tables?  I didn't think bootable was
typically used with GPT tables.  There is a bit, but it's not used to
mark EFI partitions.

Which brings me back to the partition type.  Isn't that the right way
to find the EFI?

> We could switch over to using the generic load from CONFIG_CMD_FS_GENERIC if there's demand for non-FAT filesystems. We're currently using fatload because the EFI partitions in our Windows images are always FAT formatted.

You're original search method required the partition be FAT.