[Q] Back to Stock Kernel? - Nexus One Q&A, Help & Troubleshooting

I've played with a lot of great kernels lately, but it is getting hard to compare them against the stock kernel, as I haven't used that in a while. I'd like to get back to the stock kernal (using a almost-stock ROM)
My question is: How can I get back to the stock kernel? Is there a zip file I can flash somewhere (searched and couldn't find)? I could Nandroid back, but I don't want to have to redo a bunch of tinkering I've done lately.
If not, can I push the stock kernel to the phone via ADB? After searching, it seems that the kernel is in the boot.img? Can I just grab a stock boot image from FRG83 and flash it to the phone via ADB command line/ terminal? Something tells me it's not that easy.
I've also read alot about building a kernel in linux using repositories and repacking it. I'm not sure I am up for that quite yet...

tech338 said:
I've played with a lot of great kernels lately, but it is getting hard to compare them against the stock kernel, as I haven't used that in a while. I'd like to get back to the stock kernal (using a almost-stock ROM)
My question is: How can I get back to the stock kernel? Is there a zip file I can flash somewhere (searched and couldn't find)? I could Nandroid back, but I don't want to have to redo a bunch of tinkering I've done lately.
If not, can I push the stock kernel to the phone via ADB? After searching, it seems that the kernel is in the boot.img? Can I just grab a stock boot image from FRG83 and flash it to the phone via ADB command line/ terminal? Something tells me it's not that easy.
I've also read alot about building a kernel in linux using repositories and repacking it. I'm not sure I am up for that quite yet...
Click to expand...
Click to collapse
If you can get a stock boot.img (that you're sure matches up with what you're running), you should be able to flash that while in hboot mode with the following command:
Code:
fastboot flash boot boot.img

errr I would definitely advise against just flashing the boot.img
Those updated kernels often bring re-compiled modules (like for WiFi), if you just flash the boot.img, the stock kernel won't be able to interface with those modules and you could have all kinds of bugs.
Plus (although I'm not sure), I think you need more than the boot.img and modules...

Good catch. I forgot about that aspect. Though I suppose you could flash the boot.img and push the various required modules. But it would really just be easier to reflash a stock rom.

Related

ROM Manger: Is it needed? (Anymore)

Its a great program and all. I however dont flash roms. All I do is just update my kernel, I use one of existz's kernels. Anyway, I use Quickboot to boot into recovery to flash new kernels, and it seems to work fine. Recovery is Recovery, right? I've read a few things about SGS Kernel flasher, but have also read it can cause some issues.
The only reason I could ever see for ROM manager would be if you lost your copy of CWM.
Sent from my SAMSUNG-SGH-I897 using XDA App
rom manager is only good for getting CWM onto your stock rom
So I should keep it? Just wondering. Trying to get rid of unused crap on my phone.
The only problem I've had with Kernel Flasher is getting in a hurry and forgetting to disable my lagfix (guar anteed bootloop).
I see. Ive never disabled it with CWM through ROM Manager. Am I supposed too?
i dunno what/where he was coming from talking about kernel flasher.
we were talking about rom manager...
if your kernel has CWM built in you do not need Rom Manager and the update.zip file.
CWM is BUILT IN to the kernel.
so if you dont need it get rid of it.
Oh. Ok...ya I dont rename anything to update.zip anymore. Let me read and see if that kernel has CWM
you dont normally rename anything. in rom manager the first button is download CWM. it downloads update.zip to your root SDcard directory and it uses that to "re-install package" from 2e 3e recovery. if you never see 2e/3e recovery anymore your kernel is probably CWM. what kernel are you using?
I use existz Captivate Kernel #8 lol. I don't think it has another name.
ConeyKiller said:
Its a great program and all. I however dont flash roms. All I do is just update my kernel, I use one of existz's kernels. Anyway, I use Quickboot to boot into recovery to flash new kernels, and it seems to work fine. Recovery is Recovery, right? I've read a few things about SGS Kernel flasher, but have also read it can cause some issues.
Click to expand...
Click to collapse
Op said he didn't like kernel flasher. Thought I would throw that out since he said all he wanted to do was flash a new kernel.
I have it. I never use it.

Question about Security on/off

I was beak bootloader using fastboot. Everything was ok then i try to use miui and CM kernel.
And i follow this this thread http://forum.xda-developers.com/showthread.php?t=934965 to make Security on. For no reason but now i wanna flash a new kernel but i can't.And can't flash ROM too.
Now i wanna S-off to flash a new kernel. I was try to use fastboot but that said
INFODevices was already unlocked!.
What can i do for S-off to flash a new kernel. Please help me.
You don't need S-off to flash a kernel you just need a custom recovery. Flash Amon Ra or clockwork mod 2.X and then try and flash the kernel through recovery.
I'm using clockmod recovery. i can't flash a new kernel through recovery too. what can i do now? please help me.
thanks so much
Why can't you flash a new kernel? Does it come up with any errors? There shouldn't be anything preventing it unless the download is corrupt, or it isn't for your phone.
My files is not corrupt. If these file corrupt i can't unzip in windows. When i'm flash a new kernel everthing is notice done well and a ROM too. But nothing happened.
I don't know if my phone or is a reason in this case. Actually this is my phone.
So, it seems like it flashes, but it actually doesn't? Or you try to flash it and it errors out?
Thanks all for helping me. I was try over 20 files then i still don't know some file can flash and some can't.
Thanks you all again.
The only way to tell that your flash worked is to check your kernel version in Settings -> About Phone. Otherwise, there isn't much of a difference.

Question about CWM for the GT-P7310 w/ official ICS

Hey all,
I just wanted to clarify this to ensure that my understanding of the Samsung recovery partition is accurate (which it very well may not be). Am I wrong in assuming that the kernel and the recovery are all located on the recovery partition for Samsung devices? I flashed the official ICS build via ODIN, and I'm wondering if it'd be a bad idea to flash an existing version of a CWM recovery.img while running the official ICS build. I don't want to flash an older kernel, but would obviously like to obtain root.
If that ends up being the case, I assume that I'd have to build a new CWM using the stock ICS recovery as a base? Sorry for the noob questions, I'm just trying to get a better understanding of how things are working under the hood for this thing.
Thanks!
AFAICT the recovery.img and the boot.img are in distinct partitions on the device. The default is to boot the stuff in boot.img (which consists of a descriptive header, a kernel image and a ramdisk image). I'm not sure (yet) of the format of the recovery.img but I wouldn't be surprised if it's formatted similarly (but don't quote me ). The recovery.img is only used if you use the 'download/recovery menu'.
The main point is that they _are_ distinct. So using a CMW recovery is fine with a Stock ROM.
Replacing the kernel, however, is a different matter. It requires basically reconstructing the boot.img 'on the fly'. If you want to see an example check out the updater-script for Motley's kernel.
As for root & CWM packages, see nirogu's excellent thread about it: http://forum.xda-developers.com/showthread.php?t=1406137

[Q] How to flash CWM/TWRP recovery on ICS (stock)?

From what I searched this thread and others, I believe this is not possible, because a CRC check in bootloader or kernel I think.
Now that sources are out, couldn't we flash RECOVERY + Kernel (maybe downgrade bootloader) at the same time and avoid the bootloop?
This is not my current phone anymore so I'm not really up to date to the new developments, but, there is nooby's repack, that allows CWM, couldn't that mod somehow be applied directly to 30B (or any ICS version) trough adb or something?
Alternate solution: ?
Going to recovery atm resets the phone to factory settings, as that is the way the default recovery acts, and actually I don't need a working recovery, a way to block the phone to reset itself is also acceptable!
Flash Image Gui
I think my question was not understood properly, so I'll try to reformulate it:
Flash Image Gui is a program that allows kernel images to be flashed on HTC one S directly from Android. If the cip inside our Black is somehow compatible, we could hack the program to flash a recovery friendly kernel.
Now, is that possible?
mihaiolimpiu said:
I think my question was not understood properly, so I'll try to reformulate it:
Flash Image Gui is a program that allows kernel images to be flashed on HTC one S directly from Android. If the cip inside our Black is somehow compatible, we could hack the program to flash a recovery friendly kernel.
Now, is that possible?
Click to expand...
Click to collapse
Problem is nothing to do with kernel. Possible reason for it not working :
Bootargs incompatible
Bootloader locked
CRC bootarg forbids running custom kernel/recovery.
I'm leaning towards the 3rd one, but either way it won't work.
It's not so hard making a program like that for our phone. You just need a program that extracts the boot.img replaces the new zImage and packs the boot.img again and flash it to device. You can make a script that does that from your phone.

N00b conformation: root not needed to install CWM?

As I understand it by reading the threads, FAQ, etc. I do NOT need root to install CWM. Is that correct?
I'm trying to get my head wrapped around the differences, because on Samdung devices, you cannot get CWM installed without root.
The bottom line is I want to install CyanogenMod. That's what I'm bying the Xperia for.
I need both CWM and unlocked bootloader to do that, correct?
Hi again lol
If your device is unlocked, the best way to get recovery is to flash a kernel that has recovery included.
Usually CM comes in a zip file, inside the zip there is a boot.img file. Extracting that file and flashing it via flashtool provides you with a recovery, root, and a bootable kernel. From there on, you'll only need to flash the zip file from recovery to get a working rom.
DrKrFfXx said:
Hi again lol
If your device is unlocked, the best way to get recovery is to flash a kernel that has recovery included.
Usually CM comes in a zip file, inside the zip there is a boot.img file. Extracting that file and flashing it via flashtool provides you with a recovery, root, and a bootable kernel. From there on, you'll only need to flash the zip file from recovery to get a working rom.
Click to expand...
Click to collapse
That's exactly what I needed to know, because on the S3, the recovery is separate, so flashing the zip doesn't do anything to the custom CWM recovery version you have installed.
Just to clarify: The CM file includes the ROM, the kernel, and a CWM recovery in the zip and the current CWM recovery will be overwritten by it?
I can use flashtool and I don't need to install the zip via CWM recovery?
donalgodon said:
That's exactly what I needed to know, because on the S3, the recovery is separate, so flashing the zip doesn't do anything to the custom CWM recovery version you have installed.
Just to clarify: The CM file includes the ROM, the kernel, and a CWM recovery in the zip and the current CWM recovery will be overwritten by it?
I can use flashtool and I don't need to install the zip via CWM recovery?
Click to expand...
Click to collapse
The last time I checked, yes, kernel, rom and recovery are included in the zip. Although I don't know about latest 4.3 builds, been away from CM a couple of weeks, but the first builds lacked recovery.
You will still need to flash the zip via recovery, because flashtool uses another type of images (.ftf files). On flashtools you can only flash the kernel (boot.img), the kernel includes recovery, from recovery you can flash the zip file containing the rom. So you need two separate steps to flash CM for the first time. Next time, for updating, you will need to flash the zip via recovery and the recovery will be overwritten.
DrKrFfXx said:
The last time I checked, yes, kernel, rom and recovery are included in the zip. Although I don't know about latest 4.3 builds, been away from CM a couple of weeks, but the first builds lacked recovery.
You will still need to flash the zip via recovery, because flashtool uses another type of images (.ftf files). On flashtools you can only flash the kernel (boot.img), the kernel includes recovery, from recovery you can flash the zip file containing the rom. So you need two separate steps to flash CM for the first time. Next time, for updating, you will need to flash the zip via recovery and the recovery will be overwritten.
Click to expand...
Click to collapse
So, okay:
I use the stock kernel/ROM currently installed to use flashtool to flash the extracted kernel from the zip, but to use the custom kernel, I need an unlocked bootloader.
Is that correct?
You mentioned in the other thread your comments on CM. I am curious to know more of what you think. In the S3, the problems were related to the lack of userspace drivers, but it was my understanding that the Z was more friendly and had better driver support.
Is the sound quality that much different? By that, I mean is there increased signal noise? I'm not into special effects and tweaks, but the Wolfson DAC on the S3 was about the best I've heard and didn't need anything to make it sound great. What the lack of userspace drivers did was introduce noise into the audio that did not really exist on stock.
I'd appreciate your thoughts on the camera and sound. I also assumed the battery drain issues would be resolved. Is that not the case? I mean, with proper managment, I was able to approach stock battery levels, camera was fine, but sound was never close to stock.
So, okay:
I use the stock kernel/ROM currently installed to use flashtool to flash the extracted kernel from the zip, but to use the custom kernel, I need an unlocked bootloader.
Is that correct?
Click to expand...
Click to collapse
You can't install any separated kernel if you are locked. Because it needs ADB access via fastboot, and on locked devices you have no access to that option. Kernels with embedded recovery are custom, unsigned kernels. Locked devices don't run unsigned kernels.
If you are locked you will need to root first to install a recovery. But even with recovery installed, you won't be able to install anything but stock (kernel) based roms.
You mentioned in the other thread your comments on CM. I am curious to know more of what you think. In the S3, the problems were related to the lack of userspace drivers, but it was my understanding that the Z was more friendly and had better driver support.
Click to expand...
Click to collapse
ยก
The last time I checked the sound quality from the headphone out, the sound was unbearable. High noise, low instrument separation and soundstage, lack of bass extension and recessed mids. Very poor quality when paired to my Sennheiser Momentum.
I'd appreciate your thoughts on the camera and sound. I also assumed the battery drain issues would be resolved. Is that not the case? I mean, with proper managment, I was able to approach stock battery levels, camera was fine, but sound was never close to stock.
Click to expand...
Click to collapse
I heavily underlvolted my device, greenify every other app, etc, and I was barely getting 4.5h of screen time.
On stock based I am getting 6h of screen time. Same settings. Same brightness.
Camera launches faster on CM, much much faster, so point and shoot might work better on CM. But there seem to be too much noise, even in normal light conditions.

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