Use this script to convert objdump output to a binary file

objump2shellcode.pl

# usage: objdump -D test.exe | perl this_script.pl > file.shellcode

while(<>){                                                                                                             
  if (/^\s[\dA-Fa-f]+:\s(.*?)\s{2}/) {                                                                                 
    foreach(split(/\s/,$1)){                                                                                           
      printf pack('H*',$_) ;                                                                                           
    }                                                                                                                  
  }                                                                                                                    
}