tag 919012 + fixed-upstream thanks fyi, a later revision of these patches appears to now be merged upstream if you'd rather ship those:
9223eff8f mkimage: Clarify file alignment in efi case a51f953f4 mkimage: Align efi sections on 4k boundary e347f40c1 mkimage: Use EFI32_HEADER_SIZE define in arm-efi case
