Well, I am in the design phase right now, just ordered the tablet.
Getting the boot logo in landscape mode is the least of my concern, I am more concern about everything else, specially how the tablet integrate with the rest of the hardware
I can help with other stuff (than the boot logo 'problem') as I've set my TabS2 to provide a sort of Driver Information System (DIS) for my campervan.
Some of the changes I've made are as follows:
1. Auxiliary output from vehicle radio to 3.5mm jack on TabS2 so it can use the vehicle's excellent speakers. Bought the connector on the internet but some modern vehicles come with a connector fitted.
2. Fused electrical connection from 12V Cigar Lighter feed through 12V-to-USB (5V) mini-connector (also bought on internet) to TabS2.
3. Wifi reversing camera (GoVue RVS-020813) connected to reversing light 12V power feed. (Wifi because I didn't want to hardwire through the vehicle).
4. Created a slide-in frame on dashboard using plastic name holders, with draught-excluder tape behind to hold TabS2 off vibrating stuff.
5. Rooted the TabS2.
6. System/bin/lpm file moved sideways and replaced with one that contains
#!/system/bin/sh
su
/system/bin/reboot
which forces the TabS2 to boot when power is applied (via mini-USB connector). ie. when the vehicle is switched on and power then goes to the 12V cigar-lighter circuit and also the spur connection via the 12V-to-USB connector to the TabS2.
7. Replaced the boot animation (not boot logo) with my own animation in landscape. For which I used Samsung Theme Designer (look on Youtube for how to do this).
8. Enforced landscape mode (for post-boot animation) using the 'Set Orientation' app for those applications I have that are otherwise restricted to portrait mode (the inbuilt portrait/landscape setting doesn't work for these).
9. Bought/installed 'Sygic for Truck' navigation app.
10. Installed 'Govue' app to use with reversing camera.
11. Using 'Cronoid' app got it to fire up Sygic on boot.
12. Using 'Automagic' (premium) created flow to check for reversing camera (ie. when actually reversing vehicle, reversing camera gets power and Govue wifi pops up. This daemon checks for it). When it is detected the Govue app fires up to display the picture. This flow also checks for when vehicle stops reversing (forward gear or neutral selected); it then kills the Govue app and displays Sygic navigation.
13. To ensure everything could be controlled via the screen (a bit difficult getting to the buttons on the edges when you're driving along), I downloaded one-touch 'ScreenOff' and 'Power Off Click' icon apps for sleep and power-off, respectively. The 'Handy Soft Keys' app allows a touch at the top of the screen which will display icons to avoid using the physical buttons. The volume is easily controlled with swipe down from the top and moving the displayed slider as needed. (Note that the power cannot be switched off while there is power via the mini-USB connector, which also means that when it is being charged it will always be booted up).
The Tab S2 is a very good bit of kit. The reason for the sliding method of attachment is because it is far too useful to devote entirely to 'Head unit' duties. I use it as my everyday slate (it also means it isn't on show to potential thieves when I park up).
Was all the above necessary. It's a moot point. I enjoyed doing it. At that time I was able to spend the hours researching the techniques on the internet.
Hope this gives you some ideas.
