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[Q] Kernel questions

Hi,
I had a few questions about kernels...hope someone can help me in answering these...
I am thinking of trying out the Netarchy kernel on my Nexus S, but i was just wondering is there anywhere I can download the stock kernel (so that if anything does go wrong i dont have to do a full nandroid restore?)
Also, when installing a new kernel does that wipe data (of course I will make a backup etc before installing it, but should all my settings and apps etc remain intact normally?)
what impact does an OTA update have if i am running a non stock kernel? so say i am using Netarchy's kernel, and google releases a new OTA update...will i still be able to install the update? If i do, will it revert to stock kernel?
Thanks in advance,

brownmonkey said:
Hi,
I had a few questions about kernels...hope someone can help me in answering these...
I am thinking of trying out the Netarchy kernel on my Nexus S, but i was just wondering is there anywhere I can download the stock kernel (so that if anything does go wrong i dont have to do a full nandroid restore?)
Also, when installing a new kernel does that wipe data (of course I will make a backup etc before installing it, but should all my settings and apps etc remain intact normally?)
what impact does an OTA update have if i am running a non stock kernel? so say i am using Netarchy's kernel, and google releases a new OTA update...will i still be able to install the update? If i do, will it revert to stock kernel?
Thanks in advance,
Click to expand...
Click to collapse
I'm not aware of anywhere that the stock kernel is available for download so doing a NANDroid backup is really your best option. If you have anything that deviates from stock (kernel, rom, theme, even just deleted stock apps) it will prevent you from being able to successfully update from an OTA.
You can find a lot of information about all the available kernels here just scroll down to the third post and you'll find the info.
Finally, just as a note of personal opinion, getting OTA updates is a little overrated. If you run a custom ROM, the OTAs will be included in those ROMs eventually so you won't have to worry about restoring a stock ROM just to get the updates.

kenvan19 said:
I'm not aware of anywhere that the stock kernel is available for download so doing a NANDroid backup is really your best option. If you have anything that deviates from stock (kernel, rom, theme, even just deleted stock apps) it will prevent you from being able to successfully update from an OTA.
You can find a lot of information about all the available kernels here just scroll down to the third post and you'll find the info.
Finally, just as a note of personal opinion, getting OTA updates is a little overrated. If you run a custom ROM, the OTAs will be included in those ROMs eventually so you won't have to worry about restoring a stock ROM just to get the updates.
Click to expand...
Click to collapse
Thanks for the quick answer. I had read that post before (it was actually how i came to discover kernels ). The reason why I was asking about the OTA is because I actually use the stock ROM but was just thinking about trying out the Netarchy kernel just to see what its all about. Hence if there is an OTA update, and i am running a different kernel to the stock, is the only way for me to incorporate the update by flashing the new stock rom and then reinstall the netarchy kernel?
Also, if i install it, do you know if it wipes data/apps?
Thanks

brownmonkey said:
Thanks for the quick answer. I had read that post before (it was actually how i came to discover kernels ). The reason why I was asking about the OTA is because I actually use the stock ROM but was just thinking about trying out the Netarchy kernel just to see what its all about. Hence if there is an OTA update, and i am running a different kernel to the stock, is the only way for me to incorporate the update by flashing the new stock rom and then reinstall the netarchy kernel?
Also, if i install it, do you know if it wipes data/apps?
Thanks
Click to expand...
Click to collapse
I apologize as I forgot to mention that part of your question, I'm sick with the flu and a little out of it on some cold medications lol. You only lose data and apps when flashing if you wipe the /data partition in mounts and storage and this is not required nor is it recommended when flashing a kernel. Sorry for answering out of order, but I thought I should clear that up first. As to the other question, you have it correct; you would need to flash the new update ROM and then flashing a new kernel.
I should also note that whenever you install a new ROM, you will need to reflash a custom kernel. This is because the vast majority of ROMs released include a kernel and when you flash them it will overwrite whatever kernel you currently have.
Finally, if you have any other questions you can always feel free to post them on that thread. I'm the one who wrote it and I check it often to try and answer questions as best and as quickly as I can. Happy flashing!

Are you using a custom ROM? Flashing CM7 has the stock kernel. There are probably other ones out there that includes stock kernel with them such as OTA.

how can I revert flashed kernel settings

so I, for the first time, flashed that new kernel on the front page of this discussion which overclocks the cpu. I have the newest version of jellybean installed so I considered that a stock based rom and thought it would work. in power svae mode the screen would go all crazy, balanced mode it was aalright except it would crash after a while. peformance mode would crash even sooner. so I found a stock based kernel and flashed that. Everything is fine now except the previous kernel changed some settings on the screen rresolution or something with the gpu which increased screen size I guess cause now my custom Hubs GUI is all spaced out which I had previously and meticulously spaced before hand. it caused smaller screen titles and smaller widgets basically making things look out of proportion. is there a way to revert those settings? it seems since the stock kernel doesnt innately change gpu settings that it didnt revert the settings initially set by the first kernel. the kernel I flashed to fix it was a stock kernel slightly modified from cleanrom to do something dpi and some other unimportant thing so it isnt the completely stock kernel but it is stock based. does anyone think If I flash a true stock kernel it will get fixed? if so can I get a link to said kernel or will I have to extract it myself from a stock rom

spidasense said:
so I, for the first time, flashed that new kernel on the front page of this discussion which overclocks the cpu. I have the newest version of jellybean installed so I considered that a stock based rom and thought it would work. in power svae mode the screen would go all crazy, balanced mode it was aalright except it would crash after a while. peformance mode would crash even sooner. so I found a stock based kernel and flashed that. Everything is fine now except the previous kernel changed some settings on the screen rresolution or something with the gpu which increased screen size I guess cause now my custom Hubs GUI is all spaced out which I had previously and meticulously spaced before hand. it caused smaller screen titles and smaller widgets basically making things look out of proportion. is there a way to revert those settings? it seems since the stock kernel doesnt innately change gpu settings that it didnt revert the settings initially set by the first kernel. the kernel I flashed to fix it was a stock kernel slightly modified from cleanrom to do something dpi and some other unimportant thing so it isnt the completely stock kernel but it is stock based. does anyone think If I flash a true stock kernel it will get fixed? if so can I get a link to said kernel or will I have to extract it myself from a stock rom
Click to expand...
Click to collapse
You can't use custom OC kernel with stock rom. You need to flash custom rom like Cleanrom and you can flash what ever kernel you want that designed for CleanRom.

buhohitr said:
You can't use custom OC kernel with stock rom. You need to flash custom rom like Cleanrom and you can flash what ever kernel you want that designed for CleanRom.
Click to expand...
Click to collapse
ooh I see. the kernel I flashed was the clemsyn kernel and I just saw that it was for clean rom. damn ok lesson learned. anyway to revert the setings it changed on my gpu?
p.s. can I flash roms on my tablet without losing app data or settings or my hub UI settings? im on 4.1.1

spidasense said:
ooh I see. the kernel I flashed was the clemsyn kernel and I just saw that it was for clean rom. damn ok lesson learned. anyway to revert the setings it changed on my gpu?
p.s. can I flash roms on my tablet without losing app data or settings or my hub UI settings? im on 4.1.1
Click to expand...
Click to collapse
You should able to flash cleanrom without losing any data, during the install there're options for many kernels, I suggest try the "_that stock kernel" first

spidasense said:
ooh I see. the kernel I flashed was the clemsyn kernel and I just saw that it was for clean rom. damn ok lesson learned. anyway to revert the setings it changed on my gpu?
Click to expand...
Click to collapse
Anyone else with an unlocked bootloader uses a custom ROM that sets the display dpi. This has nothing to do with the GPU, it's just a setting that tells Android the display resolution so that it can scale UI elements accordingly.
To get your 240 dpi back, either install CleanROM Inheritance, or the first kernel in this thread:
http://forum.xda-developers.com/showthread.php?t=2106689

that is actually the kernel Iflashed to ttry and fix the dpi. thanks for informing me on that, I had a hunch dpi had something t odo with the problem I was having. I only tried one of them I guess theother one (ill have to check my sd card to find out which one ) will fix it.
and to be clear, I can flash clear rom inheritince and not lose app data or settings?
Sent from my ASUS Transformer Pad TF700T using xda app-developers app

Help, Unable to flash kernel

Hi,
I have a issue that im not used to... i recently got a Nexus 5, and first thing i did was to unlock, root and install aokp rom(nightly)
Then i wanted to install Franco Kernel, using Francos own app to try flash... the device reboots, and are stuck on the google logo.
Have no other choice to enter fastboot mode, and reflash rom(to have it overwrite the kernel), and it starts up again.
Then tried to download kernel zip and flash it in TWRP instead, but with the same result. Also tried changeing to CWM but it doesnt work with encrypted devices.
I have always used AOKP + Franco Kernel on my older devices, but now it seems impossible.
I dont know why it doesnt work, but i have some ideas, and hope someone can put me in the right direction.
1. My device is encrypted and that makes it fail.
2. AOKP lastest nightly rom is not compatible with Franco Kernel or vice versa.
3. Something is broken...
Regards
Ranarn

aokp is cm based(CAF) i believe, which would make it incompatible with any aosp kernels.

simms22 said:
aokp is cm based(CAF) i believe, which would make it incompatible with any aosp kernels.
Click to expand...
Click to collapse
Ah that makes sense, but i guess something have changed then, since i have AOKP + Franco running on 2 older devices.

ranarn said:
Ah that makes sense, but i guess something have changed then, since i have AOKP + Franco running on 2 older devices.
Click to expand...
Click to collapse
yea, just last week cm source went back to CAF.

I know chaos kernel is CAF supported, I would give that a shot. I am still running 9.1 and it works the way I want it to for me (before they went CAF).

mistahseller said:
I know chaos kernel is CAF supported, I would give that a shot. I am still running 9.1 and it works the way I want it to for me (before they went CAF).
Click to expand...
Click to collapse
Ah thanks alot for the answers... not i know what kernels i can look for...

[Q] Flashing any kernel other than Franco corrupts UI

Hello!
I've had a search of my issue but so far not been able to find any related answers
I'm wanting to try the other kernels that are available, Trinity, Elemental etc However, when i flash the different kernels it leaves the UI of the current ROM installation corrupt and I can't even get past my lock screen. Status bar is at the bottom and the rest of the UI is shifted up. Reflashing franco fixes the problem and the ROM returns to normal.
Is this simply a case of needing to reinstall the ROM, and I'm just being lazy and expecting kernels to be swappable like this?
Many thanks for any help.

mebbez said:
Hello!
I've had a search of my issue but so far not been able to find any related answers
I'm wanting to try the other kernels that are available, Trinity, Elemental etc However, when i flash the different kernels it leaves the UI of the current ROM installation corrupt and I can't even get past my lock screen. Status bar is at the bottom and the rest of the UI is shifted up. Reflashing franco fixes the problem and the ROM returns to normal.
Is this simply a case of needing to reinstall the ROM, and I'm just being lazy and expecting kernels to be swappable like this?
Many thanks for any help.
Click to expand...
Click to collapse
because you are on franco kernel, you will need to dirty flash your rom first(without wiping anything). franco kernel also changes system files. dirty flash your rom, gapps, and new kernel, then boot up.

simms22 said:
because you are on franco kernel, you will need to dirty flash your rom first(without wiping anything). franco kernel also changes system files. dirty flash your rom, gapps, and new kernel, then boot up.
Click to expand...
Click to collapse
Thanks a lot for the fast reply. I'll give it a shot!
Does dirty flashing the rom have an effect on the overall performance? Is it always better to do a clean install when trying to get the most out of your device?
Thanks again.

mebbez said:
Thanks a lot for the fast reply. I'll give it a shot!
Does dirty flashing the rom have an effect on the overall performance? Is it always better to do a clean install when trying to get the most out of your device?
Thanks again.
Click to expand...
Click to collapse
na, doesnt affect a thing. i dirty flash nearly 100% of the time

simms22 said:
na, doesnt affect a thing. i dirty flash nearly 100% of the time
Click to expand...
Click to collapse
brilliant, i've done the dirty flash and now trying out elemental kernel and working with no issues at all.
Thank you so much for the help.
ps. praise science for OTG cables!

mebbez said:
brilliant, i've done the dirty flash and now trying out elemental kernel and working with no issues at all.
Thank you so much for the help.
ps. praise science for OTG cables!
Click to expand...
Click to collapse

[Q] Can't set CPU speed on Lollipop

Hi all,
I just installed Nameless ROM and am having trouble setting the CPU speeds. I've tried with Device control (built in) and then with No Frills CPU, both with root access, and have not had any success setting my CPU speed. When I set anything on minimum, I exit the app and when I return it goes back to its original value (1574). Same thing with No Frills. I have BusyBox installed and the latest version of SuperSu. So my question is, does anyone have any idea why this is happening? Is there a workaround? Has anyone had a similar experience? I do not have a custom Kernel, but my experience in the past has been quite similar with Franco Kernel and ElementalX kernel across a number of different ROMs.
Any help would be appreciated.

Not actually a help but franco.Kernel Updater (App) doesn't work with CM12 as long as you don't install SuperSU. I did and it solved all problems. It has something to do with the internal su management I guess... but I'm not sure what's wrong with your setup since you already tried SuperSU.

Use a custom kernel.

@Lethargy: Damn, pretty simple answer! I've somehow missed that he says "no custom kernel" :S

Custom kernel
Custom kernels yield same result. Flashed Franco and the same thing is happy ING in the FKUpdater app. Forgive me if I'm wrong but the device control that's baked in to the Rom should be able to scale the kernel set in place by the same rom, right?

xkn0s said:
Custom kernels yield same result. Flashed Franco and the same thing is happy ING in the FKUpdater app. Forgive me if I'm wrong but the device control that's baked in to the Rom should be able to scale the kernel set in place by the same rom, right?
Click to expand...
Click to collapse
Whatever "device control that's baked into the ROM" makes no difference. All kernel apps/methods are the same, which is to simply echo a value (sysfs). You can do it via any kernel app, embedded kernel app, Tasker, Terminal, its the exact same thing.
What is your SELinux state?

Lethargy said:
Whatever "device control that's baked into the ROM" makes no difference. All kernel apps/methods are the same, which is to simply echo a value (sysfs). You can do it via any kernel app, embedded kernel app, Tasker, Terminal, its the exact same thing.
What is your SELinux state?
Click to expand...
Click to collapse
Did not know that. Thanks for the info!
SELinux is Enforcing.

xkn0s said:
Did not know that. Thanks for the info!
SELinux is Enforcing.
Click to expand...
Click to collapse
Try setting it to Permissive

Lethargy said:
Whatever "device control that's baked into the ROM" makes no difference. All kernel apps/methods are the same, which is to simply echo a value (sysfs). You can do it via any kernel app, embedded kernel app, Tasker, Terminal, its the exact same thing.
What is your SELinux state?
Click to expand...
Click to collapse
Lethargy said:
Try setting it to Permissive
Click to expand...
Click to collapse
Changed to permissive verified and reboot, still having the same trouble... tried flashing Franco again and went into boot loop; Same with Hellcore kernel and ElementalX kernel.

xkn0s said:
Changed to permissive verified and reboot, still having the same trouble... tried flashing Franco again and went into boot loop; Same with Hellcore kernel and ElementalX kernel.
Click to expand...
Click to collapse
Not sure why it would end up in a non-boot. Try reflashing your ROM then the kernel.

Lethargy said:
Not sure why it would end up in a non-boot. Try reflashing your ROM then the kernel.
Click to expand...
Click to collapse
Booted TWRP, Flashed Rom and ElementalX in one go, boot stuck at Google splash screen for 20 minutes. Reflashed rom and booted up. Still not able to set CPU. Tried Reflashing Franco Kernel with app again and back to Google Splash Screen.

xkn0s said:
Booted TWRP, Flashed Rom and ElementalX in one go, boot stuck at Google splash screen for 20 minutes. Reflashed rom and booted up. Still not able to set CPU. Tried Reflashing Franco Kernel with app again and back to Google Splash Screen.
Click to expand...
Click to collapse
If you reflash the ROM it'll probably go back to using it's original kernel. Have you tried with a different ROM?

Lethargy said:
If you reflash the ROM it'll probably go back to using it's original kernel. Have you tried with a different ROM?
Click to expand...
Click to collapse
Yeah I reflashed /system and it came back up.
I just flashed Terminus Rom (http://forum.xda-developers.com/google-nexus-5/development/android-5-0-0r7-lrx21v-t2950499) and set up as new device. installed Kernel Toolkit and was able to set the Clock, but after a few minutes it just went back to default.
Flashed ElementalX kernel after that and installed the corresponding app and was able to set clock without it changing back. seems to only work in ElementalX app though.
It survived a Reboot and I sat and watched it for a while and it seems to all be working now!
Thanks for your help @Lethargy

xkn0s said:
Yeah I reflashed /system and it came back up.
I just flashed Terminus Rom (http://forum.xda-developers.com/google-nexus-5/development/android-5-0-0r7-lrx21v-t2950499) and set up as new device. installed Kernel Toolkit and was able to set the Clock, but after a few minutes it just went back to default.
Flashed ElementalX kernel after that and installed the corresponding app and was able to set clock without it changing back. seems to only work in ElementalX app though.
It survived a Reboot and I sat and watched it for a while and it seems to all be working now!
Thanks for your help @Lethargy
Click to expand...
Click to collapse
ElementalX and it's app use an init.d script (as of the latest version, it uses a ramdisk script instead) to set the values upon boot, reading values from a config file.

Hi all,
For reply at first message, I think have a solution (that's worked for me). On many devices like Nexus or Xperia, a Qualcomm service can be installed and running at boot (MPDecision) and change the CPU usages when it's necessary (number of cores and frequencies).
Maybe this priority is higher than all in Lollipop, and overwrite the modifications changed in other CPU managment apps. I found this when I searched a solution to this same problem on my Xperia Z with Lollipop 5.0.2. I used lot of app and no one worked for me, and tried Kernel Adiutor to see more parameters (need install Busybox). I disabled MPDecision to the CPU Hotplug section, and the SetCPU profiles worked after.
But you can see that disable this option keep all cores enable (with MPDecision enable, many cores change status to "disconnected" when no usage) maybe it's better to use SetCPU profiles on a full day than leave MPDecision manage your CPU. Just compare.
Sorry for my bad english, and happy if this help someone.