No, you didn't download the wrong firmware.
Try following these steps to change the device back to English:
1. Connect to the web configuration utility by entering the TeraStation's IP address in a web browser.
2. In the column of blue items on the left hand side, select the second link.
3. Under the first header are two text fields; enter or modify the text in the second.
4. Under the third header, the first entry is a radio selection with two options; select the one on the right.
5. Under the fourth header (with two menu/pulldown boxes beneath it),set both menu boxes to the second entry in the list (the second menubox should say cp437).
6. Click the button, and close and reopen the browser.
If this does not fix the problem, try to reflash the firmware.If possible, it would be wise to backup any important data in case thefirmware update fails due to a power outage or other anomaly. If youhave the latest version already, you will need to force the firmwareupdate. To do this, after unzipping the files, create a shortcut to the.exe file. Then, go to the properties of the shortcut and add a spaceand /force to the very end of the target.