awesomebo.zsh

#!env zsh
set -e

function showhelp {
  echo "$0 <encryption_key.bin> <encrypted_amiibo.bin> [seven_byte_uid] [--random]"
  exit
}

function checksum {
  [[ $#1 -eq 3 ]] || [[ $#1 -eq 4 ]] || showhelp
  echo $(( $(($1[1] ^ $1[2])) ^ $(($1[3] ^ ${1[4]:-88)) ))
}

encryption_key=$1
encrypted_amiibo_bin=$2
uid_prefix=$3[1]$3[2]$3[3]
uid_suffix=$3[4]$3[5]$3[6]$3[7]

test -f $encryption_key || showhelp
test -f $encrypted_amiibo_bin || showhelp

tmpdir=$(mktemp -d awesomebo.XXXXXX)
echo "Decrypting file in $tmpdir..."
decrypted_amiibo_bin=${tmpdir}/${encrypted_amiibo_bin}.decrypted
amiitool -d -k $encryption_key -i $encrypted_amiibo_bin -o $decrypted_amiibo_bin

echo "Patching file..."
patched_decrypted_amiibo_bin=${decrypted_amiibo_bin}.patched
cp $decrypted_amiibo_bin $patched_decrypted_amiibo_bin
uid=$uid_prefix$(checksum $uid_prefix)$uid_suffix
echo "000468: $uid_prefix$uid_suffix" | xxd -r - $patched_decrypted_amiibo_bin
echo "00: $(checksum $uid_suffix)" | xxd -r - $patched_decrypted_amiibo_bin

echo "Encrypting file..."
patched_encrypted_amiibo_bin=${patched_decryped_amiibo_bin}.encrypted
amiitool -e -k $encryption_key -i $patched_decrypted_amiibo_bin -o $patched_encrypted_amiibo_bin

echo "Padding file..."
patched_encrypted_padded_amiibo_bin=${patched_encrypted_amiibo_bin}.padded
echo "00: 00040402010011030100000000808000" | xxd -r - $patched_encrypted_padded_amiibo_bin
dd of=$patched_encrypted_padded_amiibo_bin oflag=append bs=4 count=8 conv=notrunc
dd of=$patched_encrypted_padded_amiibo_bin oflag=append if=$patched_encrypted_amiibo_bin conv=notrunc
dd of=$patched_encrypted_padded_amiibo_bin oflag=append bs=4 count=108 conv=notrunc

uid_prefix=$(xxd -s 0x68 -l 3 -ps $patched_encrypted_padded_amiibo_bin)
uid_suffix=$(xxd -s 0x6C -l 4 -ps $patched_encrypted_padded_amiibo_bin)
eml=$uid_prefix$uid_suffix.eml
xxd -ps -c 8 $patched_encrypted_padded_amiibo_bin > $eml
echo "Saved as $eml"