Database Info

[Q] So what is a ROM?

Hi, I am new to the world of smart phones and would like to learn more about them. I've been reading threads about people changing their ROMs and how it can affect future software updates.
I've done some searching w/ "what is a rom" and "stock rom" but the results are in techno-wiz-lingo that's right over my head.
I have two (pretty basic) questions regarding ROMs.
1. What is a rom?
and
2. If I use Titanium Backup (and install its corresponding busybox), does this change my ROM?
Sorry for the 4th-grader-noob questions. Thanks in advance!
Cheers,
John

We all were there sometime in past, so no problem.
1. A ROM is a part of a non-volatile non-"erasable" memory in phone that hold the operating system and main applications; you can compare it to a premade install of an operating system in a Desktop computer (for example: windows 7 and what manufacturer applications has installed), the difference is that you can't modifiy a ROM directly from inside the phone.
Now, smartphones comes also with premade install os the OS, that's called 'stock ROM', a ROM that come from the phone manufacturer; some people are able to extract ROMs from certain models and modify (kitchen) it, fixing bugs, adding new features, even upgrading main OS version, in short improving what came from the manufacturer that's called 'custom ROM' and that's what xda-developers is all about, in the several forums you will see sections where they talk about improving phone usability.
2. I have no much experience with Android but it seems that titanium backup can backup all your user data, so you can flash a custom ROM to your phone then restore you user data back to your phone, so you won't need to readd everything back at hand (usually when you flash a new ROM to your phone, everything is wiped out and the phone is left blank).
Hope that helps.

Thanks Drakh, that helps a lot! I did some more reading on wikipedia. Looks like I have a bit more to learn.

Thank you also Drakh. I have a lot to learn also.

Some general ROM/Kernel questions from a newbie

Hi, I am a relative newbie to ROM flashing and the like. Additionally I dont have a very deep computer knowledge base. I have rooted my Samsung Captivate and have flashed a ROM (which flashed properly, but didn't quite work). I have three questions about ROM usage and such:
1. I know kernels basically add aspects to the ROM you are running, but when should you flash these? How do you flash them (same process as with ROMs? do you just do it over-top of the Rom you currently have loaded? etc...)
2. If a newer version of the ROM you have running comes out, do you have to start over and completely wipe the device over again and do the whole process from start, or can you load a newer version of your current ROM over the one you have?
3. I have been hearing/reading about some problems with the Android Market disappearing on certain ROMs when the market updates, how can i avoid this/fix this?
Thanks. Sorry the basic/stupid questions.

1. Yes
2. There are WIPE versions and NO WIPE version. Usually you can use the NO WIPE version and keep everything. But sometimes if the roms are too different you get problems and errors, then it is recommended to flash a WIPE version.
3. Hm did not experience this yet, but there are fixes somewhere .

Whats up... No question is a stupid one buddy.... (Sometimes )
To answer your first question about kernels. Flashing kernels aren't a must. You don't have to flash them really, unless there is a need. Kernels for the most part can often change the way Android handles stuff like memory management, battery resources and even multitasking. They change (tweak) the way the Android OS itself interacts with the phones hardware. That's all a kernel is really. So read up on them before flashing them because each has their advantages and disadvantages. For example, the kernel I use gives me a good RAM boost and much better battery life but it suffers on the multitasking side and I have to do other stuff to compensate for that. That's how it is. As far as flashing them is concerned. That depends. Usually, you just flash them through recovery (Like a ROM) but I would suggest you follow the instructions they give you (if it exists).
Your second question is simple. Just follow the instructions they give you for installation. Some ROMS require a full wipe and others don't. It just depends on the ROM. When in doubt, follow the instructions (again if it exists).
Your third question is a weird one, I've never heard about that really. BUT.... Some ROMS may or may not include the GAPPS applications (Google Apps).
If the ROM you flash doesn't have Google Apps built in, it would literally be missing. You would have to flash it separately. Usually in those cases though, at the download location for that ROM, they would also provide links for GAPPS zip files to flash separately so you can have the option to go with Android Market, Gmail and such OR you can use an alternative. Short of that..... never heard of that issue before..... If the issue is happening after the Market app updates, in that case it might be some type of ROM issue, you'll probably have to somehow get the updated Vending.apk (Android Market) remove/backup the original and reinstall it manually (the way you would a regular apk). I'm guessing though....
Don't you just love research........

Thanks. And now, inevitably, answers lead to more questions.
With regards to kernels, how do I know which one's do what, are compatible with which ROMs etc. I feel like its the kinda thing that needs a giant database for them, but i know there isn't.
Also, is the process for flashing other .zip files the same (though either Rom manager or a built in Recovery option). For example, a bootanimation.zip?
Ultimately I hate the idea of asking overly simply questions, but I just don't know what I dont know, nor what is supposedly implied. Thanks.

Don't sweat it...... I'm in the same boat so I have no hangups....
I think I know what you mean when it comes to kernels. Ultimately, learning about kernels requires a lot of reading in many forums (Just like this one)... Why?.... Because in many instances the persons posting the kernels might not always give you an exact breakdown on exactly what it does..... so I understand. Your best bet would be scanning XDA. I've found all sorts of really excellent kernels lying around and the devs here love documentation so there is a good chance you'll know what it does...
You could also try DroidBasement: http://droidbasement.com/db-blog/
They actually have just what you wanted, a database....kind of. They have a very large variety of kernels for different devices so its a good place to start as well.
They also tend to do a breakdown of what each kernel is capable of, the device it should be used on and so on.
About flashing zip files. Generally speaking, most zip files are flashed through recovery but its not written in stone. Following the instructions concerning said zip files are always very important. Always look for instructions before you do so at least at first. In the case of bootanimation.zip.... They are not always flashable. But if it is flashable, you can flash it through recovery which would be the best method....
If you want though, you can replace the original bootanimation.zip file with the new one manually, once you have root and some type of root explorer (for example RootExplorer for Android).
Generally, the boot animation directory is usually, /System/Media so you can check to see if its there and if it is, just backup the original and replace it with the new one.... That should work... Always nandroid before doing so though.... before doing anything really....

Thanks. I actually had a question about nandroid but forgot. Basically, what is it. I realize contextually that it's a backup program and apparently works through the recovery menus. I read a ROM flashing step-by-step that mentioned it but couldnt figure out where to get it (not in the market unlike Ti-bu which i use currently).

Nandroid is a backup program that basically creates a flash image of your phone... If you've ever heard of "Ghosting" or "Imaging" a Hard Drive, its exactly the same thing.
Its really as good as it gets as far as data backup is concerned. Its also a low level backup, so even file structures would be recorded.. In other words, you can completely screw up your phone (file partitions everything!!!!) but once you can boot to recovery, your phone can be restored. That's why its so important because its your safety net....
Its not something that you can install like an apk, so its not in the market.
You would have to flash a custom recovery. If you have one already, it should be located in one of the menus (It changes depending on the type (brand) of recovery).
If you don't see the option in your recovery then its probably not custom and you're going to have to do some digging on these forums and maybe a bit of googling for instructions on exactly how to do so. Because it could change from device to device.
Nandroid also allows you to backup your sd-ext partition as well, so if you switch cards, you can restore to another card.... Its really incredibly handy and I wouldn't suggest you do anything until you can create nandroid backups....

Now, I'm having an interesting problem I posted this same thing in general Captivate forums but maybe someone who is looking at this/answering me knows. here's what i posted there:
have a Captivate that I recently flashed Di11i's 7.1.1 to, before that I had flashed my first ROM which was Serendipity 6.2. Both times I have found that I don't get incoming calls. People calling me get 2-3 rings, and then a traditional "busy signal" sound. On my end, either the phone vibrates once but the screen doesnt change from whatever screen I'm on. Or, The screen goes black like its going to the incoming call screen, but the black screens only flashes and goes away, as does a force close message box that goes away quickly without me clicking it.
Everything else on my phone works as far as I can tell, I've been running my current ROM for about 5 days without issues other than this one. This same exact problem also happened when I flashed Serendipity 6.2 (which I only kept for like a day because of this problem)

Ok....I currently use a G1 and most of my experience has been on HTC Devices. I'm not sure of how to reply to this as I have never really modded Samsung devices before. So I'm not really familiar with software and hardware differences (Like Bootloader, Recoveries, Radios and such). But based on what you're describing.... It sounds like a ROM or maybe a radio issue. Maybe its an issue with the phone app itself. If the app is somehow buggy then thats exactly what would happen. When the phone rings the phone app would try to run but then force close....
I'm guessing here, but it could also be a radio issue because you're getting a busy tone as well which is not good. Maybe the ROM requires a specific Radio version BEFORE its flashed.... Check the source of the download and determine if it requires a specific Radio version.
In my experience though, if the correct radio version isn't used for a ROM that requires it, the phone just won't boot..... but then again, I don't know what would happen on a Samsung Captivate.... Not sure if I can help on this one because I don't have any info on that type of hardware. I don't own one you see.....

What about if you found out a new kernel isn't as good as the old kernel, how would you go on to take away the new kernel to replace it with the old kernel? Is it the same process or even harder?

vlen22 said:
What about if you found out a new kernel isn't as good as the old kernel, how would you go on to take away the new kernel to replace it with the old kernel? Is it the same process or even harder?
Click to expand...
Click to collapse
NOW THIS IS ANNOYING..
u have to flash ur rom again..
but fortunately u dont need to do and wiping data or partitioning sd card.. jus flash rom..

Its not something that you can install like an apk, so its not in the market.

zeemar007 said:
NOW THIS IS ANNOYING..
u have to flash ur rom again..
but fortunately u dont need to do and wiping data or partitioning sd card.. jus flash rom..
Click to expand...
Click to collapse
The rom kernel that I downloaded, or flashing clockwork recovery mod? Like adrenylyne's kernel for the thunderbolt.
EDIT: Never mind, I found out. I didn't mean any harm if MY POST was annoying.

If you have two kernels, in a flashable zip, you can just flash them over each other to exchange them (turn off any modification the kernel did befor though, like lagfix).

New question, I had an app (quick office) that came on my captivate. Now that I've flashed di11i's 7.1 I don't have it anymore. This is particularly peculiar because all the other native apps are still here:samsungs media player from example. How do I go about getting this missing app back on my phone. I have all the backup files on my computer so I should have the .apk (although I'm not entirely sure how to install those properly) thanks
Sent from my SAMSUNG-SGH-I897 using XDA App

Regarding Root Privileges

Crash course about root and roms:
I keep seeing a lot of people make comments like "I flashed xboarders rom so I could have root and then flashed CM7. Everything working great." That's not really the way it works. It doesn't hurt to do that, but you're adding an uneceasary step. Lets say you use Superoneclick, what that does is roots the stock rom you have in place. For now it works with our phones on Froyo and not on GB. So what are our options to "gain root" with GB? We have to flash an already-rooted rom. But understand that the root privileges are built in to the rom. Flashing xboarders rom or any other rom doesn't "give you root" for the other roms you might flash, it is simply one rom out of many that is pre-rooted by the dev who packaged it up. When you flash it you have a rom that is rooted. If you flash CM7 (another rom that provides root access to its system files) then you have a different rom that was pre-rooted by its dev.
Are you catching what I'm saying? Root doesn't "stick" between roms, so flashing one rom to "gain root" before flashing another doesn't really help all that much. Root privileges are built in to the rom.
If you want to unroot GB, then browse the threads in the development section. There are a couple of stock nandroid backups posted that you can restore via clockworkmod recovery and then you'll have a stock unrooted rom. You can even do that and still have clockworkmod recovery in case you want to flash a different rom to your phone again.
And just a friendly reminder to PLEASE remember when flashing from one rom to a different rom: WIPE WIPE WIPE data, cache, dalvik cache, then flash rom, then fix permissions, then reboot. This will save you SO MANY headaches.
G2X CM7

Nice buddy

I've asked a couple of n00b technical questions that nobody would answer. Like, "does the 'ROM" image contain the linux portion of the run-time?". Since "root" apparently means obtaining unix root privilege at the linux layer (again another question I've asked that nobody answered), and root follows the ROM, then I will add 1+1 and say the ROM contains the linux layer.
As a side note, a ROM is a piece of silicon (where I used to put my embedded code) that hasn't been manufactured for over a decade, so the overloading of that term is still tripping me up.
Nobody on this forum is responsible for technical training. I've looked at some android books on Safari, and all I find is UI stuff. I can't seem to find driver and IOS level stuff. Anyone know of a book about that stuff? It appears Android mostly goes thru JNI, so maybe I need to get on a JNI forum to understand how JNI connects to the linux drivers?
I could care less about app dev - I want to figure why my phone crashes.
Thanks,
-BobK

What most people mean nowadays when they refer to a ROM is a ROM image, flashable or otherwise copyable into the partitions that are set up in the phone's non-volatile RAM.
Yes, the ROM image contains Linux -- bootloader, kernel, drivers and a bunch of binaries like "busybox", dalvikvm (the dalvik virtual machine), dexopt, dhcpd, vold and so on.
EDIT: namklak: since it sounds like you know something about Linux already, you really should learn about ADB so you can login to your phone and look around. You should probably make sure you have a rooted ROM so you can run as superuser and look through / and /system/etc and /dev and /sys.

namklak said:
I've asked a couple of n00b technical questions that nobody would answer. Like, "does the 'ROM" image contain the linux portion of the run-time?". Since "root" apparently means obtaining unix root privilege at the linux layer (again another question I've asked that nobody answered), and root follows the ROM, then I will add 1+1 and say the ROM contains the linux layer.
As a side note, a ROM is a piece of silicon (where I used to put my embedded code) that hasn't been manufactured for over a decade, so the overloading of that term is still tripping me up.
Nobody on this forum is responsible for technical training. I've looked at some android books on Safari, and all I find is UI stuff. I can't seem to find driver and IOS level stuff. Anyone know of a book about that stuff? It appears Android mostly goes thru JNI, so maybe I need to get on a JNI forum to understand how JNI connects to the linux drivers?
I could care less about app dev - I want to figure why my phone crashes.
Thanks,
-BobK
Click to expand...
Click to collapse
If you're familiar with Linux then an Android ROM is basically the equivalent of a Linux distro. Its a customized version of Android that contains the Linux-based OS along with whatever modifications and default apps the developer wants to include to give it its own flavor. The name "ROM" is a bit of a misnomer since most all custom android ROMs give the user root access to the system partition. Its no longer "read-only memory" if you have read/write access. The first time I heard the term ROM used this way was in reference to copies of old Nintendo games ROM cartridges that could be run in an emulator on my computer.
Not sure about books to direct you to.
G2X CM7

Most "so-called" doesn't read. Maybe it's easier for them to post/start new thread rather than reading. They don't even care where they pot as long as they can ask, and sadly, it's the same question over and over again.
If you check Q & A (even General and sometimes Development), there are more than 2 root questions in the first and/or second pages.

Meaning of Custom roms, kernels etc.

Can anyone explain me the meaning of 1.Custom Roms
2.Kernels
3.CMW Recovery
Also Does any Custom Rom allows me to change the boot animation?
Any help would be appreciated.

OK Im goin to try
Custom ROM - you could think of it as modified version of android. Stock ROM is ROM that comes with your phone when you but it. Custom ROMs are mostly debloated (without crap apps that just slow you phone etc. and they are tweaked to run more efficiently)
Kernel is a piece of software that is a core of your OS and basically mediates comunication between hardware and applications.
CWM Recovery is a "upgrade" of default recovery. It enables you to do NAND Backups and Restores of your whole phone, and many other great features that you cant do on default recovery. Its very powerfull tool
OK I hope that this will help you
Sent from my HTC Wildfire S using xda app-developers app

pansysk75 said:
Can anyone explain me the meaning of 1.Custom Roms
2.Kernels
3.CMW Recovery
Also Does any Custom Rom allows me to change the boot animation?
Any help would be appreciated.
Click to expand...
Click to collapse
I'm new to the Android/Rooting community so take everything I say with a grain of salt. I'm still learning, but this is what I've learned in the past month of tinkering with this stuff:
1) A custom ROM is like a custom version of the software you interact with. Android by itself is not configured to each specific device it is installed on. So, the manufacturers (like Acer, Asus, Samsung, etc) take that android compilation and configure it for the devices they sell. Each of these configurations is different and some of them prevent you from having full functionality, whereas others might be bloated/slow/need other tweaks. Enter some awesome guys here on the XDA-forums and other places who took these manufacturer-specific installs and stock installs and customized them to enhance performance, battery life, change the look and feel, and offer various tweaks & fixes.
2. A kernel is the underlying code that runs the operating system. I haven't messed with this stuff yet, I don't know much about it, and if you don't know anything just DON'T mess with it. Breaking the kernel will completely prevent you from using your device (I'm applying my computer knowledge to assume the Linux/android kernel operates on the same principles as computers)
3. CWM recovery stands for clockwork mod recovery. Basically, these stock tablets and devices include a "recovery" module built-in that lets you backup your tablet and hopefully restore it in case things go horribly, horribly wrong. CWM is an after-market/3rd-party recovery that has a TON of functionality and is very well-supported and updated. Most tutorials assume you HAVE CWM recovery installed so its a pretty awesome and pretty important program to have. The CWM recovery wiki has more information depending on your model of device.
I hope this answers your questions, and if I am mistaken in any aspect I encourage another member to correct me.
Thanks,
Opethfan89

This link explains all kinds of android terminology. I was incorrect about a few things, glad I found this: link here

Thanks for your time!

pansysk75 said:
Thanks for your time!
Click to expand...
Click to collapse
as for your other question about bootanimations....you only have to be rooted to install a boot animation. and depending on the original location (some manufacturers put it in system/media orthes in a non-root required location)
find an animation you like, download it, use root explorer or another file explorer and copy it to the system/media folder and change permissions to rw/r/r and reboot and it will play the new animation.
there are also apps on the market (Rom toolbox) that has a TON of tablet specific animations, it will download them, and install them for you....and as long as you are rooted you just have to sit back and relax

What do I need to learn.!

Hi folks.
I'm new here.
It's my first post so please forgive me if there's something wrong.
Basically I want to know is, what type of knowledge do i need (programming language and other things) to work on root of android like build.prop and making custom roms and working on the custom recovery etc.
What do I need to learn to understand those things and work on them.
Thanks.

Kaksrocks said:
Hi folks.
I'm new here.
It's my first post so please forgive me if there's something wrong.
Basically I want to know is, what type of knowledge do i need (programming language and other things) to work on root of android like build.prop and making custom roms and working on the custom recovery etc.
What do I need to learn to understand those things and work on them.
Thanks.
Click to expand...
Click to collapse
Your question is not specific and I not sure exactly what information you requesting. For instance,
1 "root of android" ? Are you trying to root you're phone?
2. "build.prop"? Adding or modifying that can be done with an android app provided your device is already rooted. Ising ADB and fastboot may also be a possible.
3. " making custom roms" ? Does that mean installing or actually building a custom rom? Actually building a custom rom that is best left for advanced level developers. If, you mean installing a custun rom then generally speaking that is usually done in custom recovery by flashing a .zip file. Its very specific for each phone and carrier.
4. "working on custom recovery"? Depends on which custom recovery you have installed and what options are available. A YouTube search can provide some general information.
I am assuming you are interested in rooting you phone and unfair with all is necessary in order to do so. I suggest, searching for your specific model and carrier hear on XDA. For instence, I have a note 4, I search, "XDA Sprint Note 4".

Mr. JAVI said:
Your question is not specific and I not sure exactly what information you requesting. For instance,
1 "root of android" ? Are you trying to root you're phone?
2. "build.prop"? Adding or modifying that can be done with an android app provided your device is already rooted. Ising ADB and fastboot may also be a possible.
3. " making custom roms" ? Does that mean installing or actually building a custom rom? Actually building a custom rom that is best left for advanced level developers. If, you mean installing a custun rom then generally speaking that is usually done in custom recovery by flashing a .zip file. Its very specific for each phone and carrier.
4. "working on custom recovery"? Depends on which custom recovery you have installed and what options are available. A YouTube search can provide some general information.
I am assuming you are interested in rooting you phone and unfair with all is necessary in order to do so. I suggest, searching for your specific model and carrier hear on XDA. For instence, I have a note 4, I search, "XDA Sprint Note 4".
Click to expand...
Click to collapse
Well. First of all thanks for the reply.
I do have the knowledge on how to root the device and i have my device rooted.
I know how can i modify the build.prop file.
But i want to know how the tweaks are actually made to put them in build.prop file to get it into work. How that tweak is made.
How to know what actually should i edit and etc.
And for custom roms. I do actually want to know about how to actually make a custom rom. Even though if its a high level thing. I still want to know. So that i can start learning and get in that field.
I want to know how custom recovery is made. For ex how twrp was made. And i want to learn its functionality.
Thanks again for the reply.

Kaksrocks said:
Well. First of all thanks for the reply.
I do have the knowledge on how to root the device and i have my device rooted.
I know how can i modify the build.prop file.
But i want to know how the tweaks are actually made to put them in build.prop file to get it into work. How that tweak is made.
How to know what actually should i edit and etc.
And for custom roms. I do actually want to know about how to actually make a custom rom. Even though if its a high level thing. I still want to know. So that i can start learning and get in that field.
I want to know how custom recovery is made. For ex how twrp was made. And i want to learn its functionality.
Thanks again for the reply.
Click to expand...
Click to collapse
I
You welcome and I also Thank you for responding.
In regards to modification of build.props, I advise beginning with custom recovery and making a full back- up (all partitions). I have soft bricked my phone more that once by modifying build.pros and simply did a full wipe and restored my backup and up and running. Kernel Aduitor is an app that provides a Build prop Editor but there are stand alone app that are also available.
If your custom recovery is TWRP then Tipatch is an app that is worth looking into. Its available here on XDA or can be downloaded via Google Play Store.
Odex Roms vs Deodex Roms and what that means. I suggest Deodex if your plan on modifying and/or porting.
Also good to know the differences between kerels permissive vs enforcing.
Apps= ApkTool X, Apk Editor v1.3,(this is a lower version that offers a rebuild function while the updated version available from Google Play dose not) Md5 , and ZArchiver.
As far as how to make custom roms? Thats above my skill level. However, If you download a custom rom make a copy and rename it, then use a root file manager to extract it or ZArciver app and look threw the files of the rom. May help prove helpful in learning basic structure.
Keep in mind I am not a developer. Modified, porting, flashing, treaking I do often. For instance, Im tunning and od Note 4 on marshmallow 6.0.1 and have official Google Play Dark Theme.
If you have any questions

https://forum.xda-developers.com/android/themes/official-google-play-store-dark-theme-t3977061

Mr. JAVI said:
I
You welcome and I also Thank you for responding.
In regards to modification of build.props, I advise beginning with custom recovery and making a full back- up (all partitions). I have soft bricked my phone more that once by modifying build.pros and simply did a full wipe and restored my backup and up and running. Kernel Aduitor is an app that provides a Build prop Editor but there are stand alone app that are also available.
If your custom recovery is TWRP then Tipatch is an app that is worth looking into. Its available here on XDA or can be downloaded via Google Play Store.
Odex Roms vs Deodex Roms and what that means. I suggest Deodex if your plan on modifying and/or porting.
Also good to know the differences between kerels permissive vs enforcing.
Apps= ApkTool X, Apk Editor v1.3,(this is a lower version that offers a rebuild function while the updated version available from Google Play dose not) Md5 , and ZArchiver.
As far as how to make custom roms? Thats above my skill level. However, If you download a custom rom make a copy and rename it, then use a root file manager to extract it or ZArciver app and look threw the files of the rom. May help prove helpful in learning basic structure.
Keep in mind I am not a developer. Modified, porting, flashing, treaking I do often. For instance, Im tunning and od Note 4 on marshmallow 6.0.1 and have official Google Play Dark Theme.
If you have any questions
Click to expand...
Click to collapse
Great. Thanks for the information you provided.
You were pretty helpful.
So again thanks.