@lohtse
In the initial post there are links to posts 12 & 91 showing the 2 different methods to copy and flash region 16 (which contains the logo/splash image). Use GIR_Editor to change the image ensuring it is the same picture size as the existing one. [Only registered and activated users can see links. ]. You can use the instructions adapted for your use [Only registered and activated users can see links. ], keeping in mind that it's referring specifically to nuvi 37xx series although the steps are similar for all devices with region 16.