Reset Fortigate admin password

This allows you to reset the admin password on a Fortigate firewall without resetting the config.  This worked for me on a Fortigate 40C.

1. Connect console cable.

2. Power on unit.

3. The serial number will be displayed, e.g. FGT40C3913011545.  Or it is also on a sticker on the unit.  Copy and paste it into Notepad.

4. Prepend "bcpb" to the serial number and copy that string to the clipboard.  It should be something like "bcpbFGT40C3913011545" at this point.

5. Disconnect the power.

6. Reconnect the power.

7. When the login screen appears, you have only 10 seconds to login with the special name/password.

Enter "maintainer" for a user name.
Paste in the string you copied above as the password.

8. On successful login, you'll be at a command prompt.  Enter these commands to reset the admin password:

config system admin
edit admin
set password MyPassword123
end

That's it.

Ref: https://www.doitfixit.com/blog/2013/10/30/resetting-a-lost-fortigate-admin-password/