If you are using XS++ DO NOT FLASH FILESYSTEM (FS) FILE!!! If you do that, you will need to finalize and so far, no tool (including XS++) can't access the FS for free. If you don't finalize, you will end up with the famous "Configuration error...".
@barry7000. The menu layout (button positions) are affected by the menu.ml in the filesystem. If you have CID 51, you can only flash MAIN which will change the icons, but not the layout.
I'm getting a W850 Vodafone this week too ;)
Gonna report how flashing went.