- unzip dropbearmulti.zip
- upload on /var/bin + chmod 755

on a telnet session
- cd /var/bin
- ln -s dropbearmulti dropbear
- ln -s dropbearmulti dropbearkey
- ln -s dropbearmulti dbclient
- ln -s dropbearmulti ssh
- ln -s dropbearmulti scp
- mkdir /var/etc/dropbear
- /var/bin/dropbearkey -t rsa -f /var/etc/dropbear/dropbear_rsa_host_key

Then it's ready, You've just to add a line like:

/var/bin/dropbear -r /var/etc/dropbear/dropbear_rsa_host_key

on /var/etc/init then reboot && enjoy