Error: 'zlib' is an invalid command

Openssl on mac is compiled without zlib support. Alternative method described in this article works on my Yosemite:

dd if=backup.ab bs=1 skip=24 | python -c "import zlib,sys;sys.stdout.write(zlib.decompress(sys.stdin.read()))" | tar -xvf -

Optionaly, if you just want to convert it into tar archive:

dd if=backup.ab bs=1 skip=24 | python -c "import zlib,sys;sys.stdout.write(zlib.decompress(sys.stdin.read()))" > backup.tar

It skips first 24 bytes of Android header and then uncompresses zlib data.

Just fix it

Get latest version from OpenSSL Official Repo.

$ wget https://www.openssl.org/source/openssl-1.1.0e.tar.gz
$ tar -zxvf openssl-1.1.0e.tar.gz
$ cd openssl-1.1.0e

Configure OpenSSL with zlib support

$ ./config zlib
$ make 
$ sudo make install

Happy days

$ which openssl
/usr/local/bin/openssl