AES File Format is what’s expected as .aes file header, otherwise you get “Invalid header marker” error.
3 Octets - 'AES'
1 Octet - 0x02 (Version)
1 Octet - Reserved (set to 0x00)
If your Raspberry Pi has these typical commands, you can cd to your backup and survey for bad files by
find . -type f \( -execdir bash -c '[[ `xxd -plain -l 5 {}` == '4145530200' ]]' \; -or -print \)
EDIT Changed forum source to use triple instead of single backticks to keep command backticks visible.
which is the same plan – the header must be correct or you’ll hear. If you get a bad header, what was it?