...für alle, die irgendwann auch mal den 530 Fehler erhalten:

Schaut dann mal in die /etc/passwd, was in der Zeile für root steht, die sollte bei einem leeren Password so aussehen:
root::0:0:root:/root:/bin/sh
Wenn nicht, dann bitte die o.a. Zeile eintragen, dann sollte der Login klappen.
...

For the forgetful, or someone change the password of FTP / Telnet access
to Spark decoder, and do not know what it is, we have an option to get
it back without having to install a rescue image, because that way we
can install plugins automatic USB, so here are the solution to recover
the original password Spark, which as you know is "root" (without the
quotes).

How to use:
1. Put down your PC the plugin here attached
2. Unpack the downloaded file, obtaining the folder in / plugin / ... branch with its contents.
3. Copy the folder "plugin" to C root of pencil usb pendrive.
4. Connect the USB flash drive in the decoder.
5. Once the decoder recognizes the flash drive, I get a message inviting you install the plugin, accept the option OK.
6.
Now in the Plugins menu, have the new plugin "password_ftp_root.sh"
posicionarce just have to run it on and pressing OK, the end of the
process, pressed OK again to disable it in order not to re-run in the
next reboot of the decoder.
7. You can access via FTP or Telnet with user: root and password: root

Recommendation:
For security reasons it is advisable to switch to a new custom
password, you can go to the menu System-> Net Settings-> FTP
Password, type the Old Password "root" (without the quotes), and set the
new password you wish to access from console Telnet and / or FTP
client.