At some poing over the last week, the bootx64.efi file has grown
past the 800KB threshold, resulting in being unable to copy it to
the EFI/BOOT directory.
# stat -f %z efiboot.znWo7m
819200
# stat -f %z stand-test.PIEugN/EFI/BOOT/bootx64.efi
842752
The comment in the script that creates the ISOs suggests that 800KB
is the maximum allowed for the boot code, however I was able to
boot an ISO with a 1024KB boot partition. Additionally, I verified
against an ISO from OtherOS, where the boot EFI partition is 2.4MB.
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