SSH Error: SSH startup: Unable to exchange encryption keys

[freeseacher]

Hi!
i got that error with old mikrotik

> system routerboard print
       routerboard: yes
             model: "SXT 5HnD"
     serial-number: "292901552E3D"
  current-firmware: "2.32"
  upgrade-firmware: "2.32"

the code is

class SSHIOStream(IOStream):
    SSH_KEY_PREFIX = os.path.join("var", "etc", "ssh")

    def __init__(self, sock, cli, *args, **kwargs):
        super(SSHIOStream, self).__init__(sock, *args, **kwargs)
        self.cli = cli
        self.script = self.cli.script
        self.logger = cli.logger
        self.session = libssh2.Session()
        self.channel = None

    @tornado.gen.coroutine
    def startup(self):
        """
        SSH session startup
        """
        user = self.script.credentials["user"]
        self.logger.debug("Startup ssh session")
        try:
            self.session.set_trace(libssh2.LIBSSH2_TRACE_SOCKET | libssh2.LIBSSH2_TRACE_TRANS)
            self.session.session_method_pref(20,"diffie-hellman-group1-sha1")
            self.session.startup(self.socket)
            host_hash = self.session.hostkey_hash(2)  # SHA1
            self.logger.debug("Connected. Host fingerprint is %s",
                              host_hash.encode("hex"))
            auth_methods = self.session.userauth_list(user).split(",")
            self.logger.debug("Supported authentication methods: %s",
                              ", ".join(auth_methods))
            # Try to authenticate
            authenticated = False
            for method in auth_methods:
                ah = getattr(self, "auth_%s" % method, None)
                if ah:
                    authenticated |= ah()
                    if authenticated:
                        break
            if authenticated:
                self.logger.debug("User is authenticated")
            else:
                self.logger.error("Failed to authenticate user '%s'", user)
                raise self.cli.CLIError("Failed to log in")
            self.logger.debug("Open channel")
            self.channel = self.session.open_session()
            self.channel.pty("xterm")
            self.channel.shell()
            self.channel.setblocking(0)
        except _libssh2.Error, why:
            raise self.cli.CLIError("SSH Error: %s" % why)

i got error on

self.session.startup(self.socket)

because mikrotik wants old style packet. so in console i got
Protocol error: expected packet type 30, got 34

i am using python 2.7 and libssh2 from master branch and Debian 8.4

# dpkg -l | grep libssh2
ii  libssh2-1:amd64                1.4.3-4.1+deb8u1            amd64        SSH2 client-side library
ii  libssh2-1-dev:amd64            1.4.3-4.1+deb8u1            amd64        SSH2 client-side library (development headers)