[LG Optimus 4X HD] Adam77Root:
Lot of things to comment on here. :D Very good initiative I have to admit. I'm sure I'll have more ideas as the discussion evolves. :D

Similar hardware: You can add HOX+ as laufer said. Very minor differences are there only.

What I would personally prefer is TouchWiz, at least Nature UX 2.0, but new S5 UI is also really awesome. I liked Sense till 4.5, but 5.0+ versions are now out of my 'inner circles'. :D Especially what I don't like is the UI.

Few suggestions:

FlymeOS (from Meizu MX) - I got 2.0 booting last summer, but had touchkey issues (they were freezing the device lol) and never released it. Nobody ever booted 2.0+ on other Android devices yet. :D

Porting LG roms might be the best start, I think porting full Optimus G system wouldn't be that hard. Just a pain in the *ss merging process.

What we mainly need is same screen size (unless you wanna resizing 100+ apps :p). Similar SoC is a good extra, but that's very limited. Also, it's better to avoid Qualcomm SoCs to port from, it's extremely hard, there are a lot of code changes in low-level code which just make the device get into deep segfault cycles. :cyclops: Even Exynos is easier to port from, trust me. :D I got SGS3 leaked 4.2 booting on the O4X last autumn.

Big issue we have to note: In 4.2, Google radically changed graphics libraries code. We have old, 4.1.2 blobs and those need hacks in libgui.so and libsurfaceflinger.so to function properly (in 4.4+ libEGL.so, libGLES_v1_CM.so and libGLES_v2.so also need a change). Here comes the problem: Manufacturers do change these libraries, mainly adding Wi-Fi display and HDMI support code which other blobs rely on. Of course we can't just replace these libs, graphics wouldn't function that way. Either we have to guess those function signatures and reimplement some stub in the code, or use new blobs, i.e. what I did in Omni. ;) But y'all now those are not perfect _yet_. ;)

Regarding newer kernels: If, I emphasize, IF it's properly ported, it would cause a noticeable effect on overall performance, battery life, etc. What do I mean by proper porting: All machine-specific code must be updated to Nvidia/Google upstream, no excuses! I don't say anything for sure, I didn't check it much, but kholk didn't do this merge. His kernel still uses 3.1 files with slight modifications to be 3.4-compatible. What I mean would be a very long and painful process, but would surely benefit after all. 3.4 has no Android branch, mainline Nvidia Tegra kernel does only have Linux support, it might be even harder. 3.10 is maintained by Google for Android, issues I have found so far: No graphics driver support for T2 and T3, have to forward-port it and I didn't find core Android components like wakelocks, earlysuspend, etc. Weird.

A little related story: I initially started working on MultiROM so I can test and port different roms while I can keep a stable rom for myself and there'd be no need for reflash then. That's what I can suggest. Use MultiROM, it has so many capabilities! Maybe it's better with kernel sharing so you don't have to wait for hardboot on every reboot (which one needs a lot if porting). [MENTION=4574921]MidnightDevil[/MENTION] you could add this to the OP maybe. :D

Here you are! ;) Compiled this because wanted to start porting from Note 2, but finally worked on Omni more and abandoned it.

That's way too generic unfortunately.

Quick suggestion for you port: Use Note 2 base with Note 3 features. Note 2 has the same resolution and you won't need to resize.