Update default password for X8

With new image versions, X8 does not come with default password anymore

Author: martab1994

content/hardware/04.pro/boards/portenta-x8/tutorials/01.user-manual/content.md

@@ -302,7 +302,9 @@ chmod +x 399-install-update
 sudo ./399-install-update
 ```
 
-Remember that the default password for admin access is `fio`.
+Remember to set a new admin password at your first access.
+
+***For image versions earlier than 844, the default password for admin access is `fio`.*** 
 
 Now you need to reboot the board by pressing its pushbutton for around 10 seconds. After that, connect again to your Portenta X8 through the Command Line and type the following commands:
 
@@ -759,15 +761,19 @@ At this point, you can type `adb shell` to start communicating with your Portent
 
 As it is a Linux device, you can do tasks like creating files, changing directories, etc.
 
-To gain admin (root) access, type `sudo su -` and the password, which by default is `fio`. After that, the terminal prefix should turn red.
+To gain admin (root) access, type `sudo su -` and set your own password. 
+
+***For image versions earlier than 844, the default password for admin access is `fio`.*** 
+
+After that, the terminal prefix should turn red.
 
 ![ADB shell with admin access](assets/adb-sudo-su.png "ADB shell with admin access")
 
 You can now freely program your Portenta X8 Linux OS. In the sections below you can check some basic commands to get started.
 
 ### Change Default User Password
 
-Your Portenta X8 comes with the default user fio with password fio.
+For image versions earlier than 844, our Portenta X8 comes with the default user fio with password fio.
 
 For security reasons, we strongly suggest changing the default password. To do so, when logged in to your Portenta X8, launch this command to change the password of the fio account:
 
@@ -1215,7 +1221,7 @@ Open Portenta X8 Shell as explained [here](#working-with-linux).
 sudo modprobe spi-dev
 ```
 
-Insert the user password `fio`.
+Insert the user password.
 
 An upcoming image release for the X8 will load the `spi-dev` modules automatically at boot. In the current version, please create a `/etc/modules-load.d/spi-dev.conf` file with the following content: