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General Android, kernel, build, and OTA Questions

Discussion in 'Android Devices' started by mbroowil, Nov 14, 2012.

  1. mbroowil

    mbroowil New Member
    Thread Starter

    Nov 14, 2012
    Sorry about the basic questions, but my google searches have failed me.

    It seems from other postings that:
    The 'Kernel Version' is the linux core that google uses to build their Android Version from.
    The 'Android Version' is built by google and is the core of what people eventually build custom ROMs from.
    ? The 'Build number' is the custom ROM that was built from the Android Version. ?

    Not totally understanding the process, when Jelly Bean was released I rooted my phone (Verizon Galaxy Nexus) and installed Vicious JellyBean 4.1.1 right away (by carefully following instructions and nothing else). It's worked great for me since day one, but I've never totally understood what happened.

    1) Was Vicious JellyBean the ROM? I assume he took Android 4.1.1 from Google (legitimately) and slightly customized it (just surface stuff) and made the ROM from it.

    2) Is there a ROM (if Yes is the answer to Q #1) for the Verizon Galaxy Nexus directly from Google? If not, is the original ROM from Samsung? This is the part that most confuses me. I'd really like to use the most stock option (while still allowing me to do backups, hotspots, and updates as they become available).

    3) With my Vicious JellyBean 4.1.1 ROM, can I wait for the OTA update to get 4.2? Does over the air only work if you're using an official Goolge/Samsung Build (ROM)? Does being rooted affect my ability to do OTA updates?

    4) With Jelly Bean I had to root my phone before starting so I expected to essentially 'start from scratch.' As I move forward with Android updates, will I be able to keep apps and icons installed and configured?

    Again, sorry about the basic questions (lack of my understanding), but answers to any of the questions would be appreciated.



  2. Petrah

    Petrah Psychotic Female

    Jun 13, 2011
    Annoying my X-Husband
    Hanover Park, IL
    Welcome to Android Forums, mbroowil!

    In order to better assist you, can you tell me which Galaxy Nexus you have and perhaps what carrier you're with? We can then move your thread to the appropriate All Things Root sub forums where others who have the same phone as you do can help you and answer your questions. ;)
  3. NSutherl

    NSutherl Well-Known Member

    Sep 6, 2011
    HVAC Design Engineer
    Los Angeles
    Viscous JellyBean is a ROM (a ROM is an operating system, much like Windows 7 or MAS OSx). When it's available, ROMs are built from AOSP (Android Open Source Project) code, which is taken directly from Google, who releases the source code for certain phones (the nexus line of phones) and carriers.

    Developers take this code and modify it, just like you suggested. There are a few bigger developers like AOKP (Android Open Kang Project) and CyanogenMod (CM) who actually write the new code for these modifications to make ROMs of their own, as well as share the mods for other developers to use. Other developers can take certain parts of this new code and incorporate them into their own ROMs. After flashing a few different ROMs, you'll notice that some of the mods (like AOKP's toggles or CM's nav bar) show up in a bunch of different ROMs.

    The stock ROM (factory image) from Google for the VZW Nexus (toro) can be found at the link above. These factory images are used to take your phone back to a stock, unrooted state and will wipe all of your data clean (including everything on your sd card). These are generally used when you bork something on your phone (or brick it) and need to start over.

    When looking for a ROM that suits your needs the best, the best thing to do is browse the All Things Root section here or the development section at Rootzwiki. In these forums, you'll find threads dedicated to specific ROMs so you can see the description of the mods, and follow the changelogs as the ROMs get updated by the dev.

    The only thing that affects your ability to accept OTAs is having an unlocked bootloader. If you have a custom recovery installed (like CWM or TWRP), your bootloader is unlocked and your phone will not receive OTA's.

    This isn't all that bad though, as once the AOSP code is released for a new build of Android, the developers will be working on ROMs based off of that code (and generally have ROMs up and ready within a week or 2). If, for some reason, you do want to accept an OTA, you can always flash back to the factory image from Google, re-lock your bootloader, and then wait for the OTA.

    Now that you're rooted, you have more access to apps that make this process easier. As a rule of thumb, it's a good idea to "clean wipe" when flashing new ROMs. This means you are erasing all apps and their data, all user settings (like wifi passwords, ringtone settings, etc), and the operating system from your phone before flashing the new ROM. Basically, after a clean wipe and install of a new ROM, your phone will look like it did when you first started it up after you bought it (though your sd card is not erased during this process).

    With Titanium Backup, you can backup and restore all of your apps and their data (called user apps + data), and most of your user settings (called system data). I would read this writeup by The_Chief.

    Don't forget to ask questions if you aren't sure about something, and head over to the All Things Root section where we'd all be glad to answer them :)

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