There are two common reasons why you may have locked out yourself from your MBWE:
A forgotten root password and a misconfigured sshd.
If you also can't remember your admin password, see my FAQ for the WDH1NC10000.
Reset a forgotten root password
This can be fixed as long as:
you have admin access using the web interface (also see my FAQ for the WDH1NC10000 if you can't remember your admin password)
you have not modified the passwd tools (e.g. disabled shadow passwds, use an other hash method)
By applying the following fake firmware "update":
wdhxnc-01.02.92.img,
the password is reset to "welc0me" (as in the stock WD firmware)
SSH stopped working because sshd_config is messed up
If you played around with /etc/sshd_config and then sshd stopped working,
this can be fixed as long as:
you have admin access using the web interface (also see my FAQ for the WDH1NC10000 if you can't remember your admin password)
you have ONLY modified (and messed up) the /etc/sshd_config
You have not deleted or damaged any of the other files sshd needs to work
(e.g. /etc/init.d/_SK50ssd, /usr/sbin/ssh-keygen)
The following fake firmware update replaces the broken sshd_config with the original one: wdhxnc-01.02.91.img
This update can NOT magically repair your sshd if it stopped working
for some other reason than a broken /etc/sshd_config!
General info about these firmware "updates"
You can get to the firmware upload form on your MBWE with this URL:
http://your-mbwe-ip/admin/system_firmware_manual.php
These "updates" do not really update your firmware, so the
firmware version does not change.
Also, while the MBWE says it will reboot when the "update" is
complete, I intentionally do not reboot.
Backdoor to prevent future lockouts
To prevent future lockouts, you could give access to the serial console
without the need of a password (everyone with access to the serial port
would have access to the harddisk anyway).
Instructions how to modify the inittab
to accieve this.