Hi, Thank you for reaching us. Sorry to inform we do not have a factory image that can be shipped or downloaded separately. You may upgrade it the normal way, however users are strongly encouraged to create the Dell Recovery Media. The Dell Recovery Media is the best way for the user to have a backup of the Dell factory customized Ubuntu installation with all Dell drivers, support scripts, Dell diagnostics and Recovery Media creation tools. The above mentioned step is advised only if the user wishes to go back to the factory state if he/she needs to wipe the OS , Not mandatory to create one. Thank you 
Hi I wish to upgrade my Inspiron 15 3542's ubuntu 12.04 to 14.04. So I was wondering if there's any official Dell 14.04 image available for us to use or I'd have to go the normal upgrade way? Sorry if its already asked as I googled but couldnt find any...
14.04 Official Dell Image for Inspiron 15 3542