I was working on using a grub-efi system image for aarch64 and I got the
following error:
'Error: FAT sector size mismatch (fs=1024, dev=512)'
I traced it back to u-boot¹. u-boot wouldn't chainload grub if the
device block size and the filesystem sector size doesn't line up. I
changed the line in (gnu build image) in make-vfat-image to use '-S 512'
for esp partitions and was able to load the grub menu from u-boot.

I spent some time looking through the git history but I wasn't able to
find anything to suggest why we have 1024 byte sectors there
specifically.

¹ https://source.denx.de/u-boot/u-boot/-/blob/master/fs/fat/fat.c#L589

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Efraim Flashner   <efraim@flashner.co.il>   אפרים פלשנר
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