Originally Posted by bbabiuk
I am wondering about the difference between an original development ROM vs. A stock ROM variant on a nexus device.
To explain... My last device was an HTC one. There modified stock ROMs. And then there were the aosp or rather original development ROMs. It was quite easy to differentiate. Drivers etc as well as software was very proprietary in nature vs. a stock ROM. Even the GPE ROMs were stock variants.
The question I have is....what is the difference on a nexus? Is the software similar in nature but drivers different? I likely am doing poor job explaining it...or using the incorrect terminology. But I hope I have expressed it adequately.
Not that NY of this will likely stop me from flashing a custom ROM or 10... I just was curious. That was all.
Sent from my Nexus 5 using XDA Premium 4 mobile app
On other devices, you have AOSP ROMs and Stock ROMs.
Stock ROMs cannot be compiled from source. They can have their apks decompiled and have smaller amendments made to the code that is revealed from this process and have some other basic functions added too via things like "dsi xda kitchen" and these roms generally belong in "Android development" forums. OEM's should be releasing stock kernel source code though, so this allows further amendments to be made by Stock ROM devs.
AOSP ROMs are compiled from source code as you know. Often, as the OEM can get away with only releasing kernel source code, AOSP devs have to hack drivers and libs or build open source alternatives to get things like the camera to work because the OEM may not have released the source code for the drivers or HAL. This is why on other devices, you often see early AOSP roms listing things not working like WiFi, Camera and other things that rely on hardware.
On Nexus devices, this is slightly different.
Stock ROMs on the Nexus still vary from AOSP. Google should be seen as an OEM. They have their own proprietary software such as the camera (photosphere) for example that they have not released the source code for. Obviously there is much less modification to the AOSP code for Nexus stock ROMs. Things like the frameworks will remain in large, the same. As with other device stock ROMs, the code is not directly available,. Even though it is very similar to AOSP, it isn't really. So all the ROMs in "Android development" are modified in the same way as other devices. Decompiled and "dsi xda kitchen"... Some AOSP apk's may be a direct shoe in though due to the massive similarities.
AOSP ROM devs don't have as much trouble as with other devices though. The AOSP source that is sync'd from the google repository can be built directly for the Nexus range (older devices excluded) without having to merge it with a device tree and drivers etc as the source already includes that.