Database Users

Custom kernel queries

Hi there, just want to begin by saying how amazing this community is. I'm new to whole Android scene (just came over from iOS) but what a welcome it has been! I'm blown away by the amount of ways you can customize your Nexus 7, really puts the iPad to shame
So I've rooted my Nexus 7 and am now hoping to install a custom kernel...however I have quite a few questions pertaining to this procedure.
1) How do I install a custom kernel (ie Trinity)?
2) I'm looking to improve battery life without compromising performance, what kernel would you recommend for this?
3) Can I still get OTA if I have a custom kernel?
4) Can I revert back to stock kernel and if so, how do I do this?
Sorry to come across as a newb, I saw a lot of helpful threads on custom ROMs however I found the stuff on kernels a bit daunting...Hopefully this thread will be helpful for others as well
Thanks again everyone.
Sent from my Nexus 7 using xda app-developers app

1. just flash it in recovery, dont wipe a thing.
2. trinity
3. kernels dont have anything to do with ota. if its still enabled in your rom then yes.
4. either fastboot flash a stock boot.img or just reflash your rom without wiping anything.
5.

Worth noting that when a new rom is installed it installs its own kernel so you'll have to reflash your kernel.
I also recommend faux for good battery life. Both that and Trinity are good.
Sent from my LG-P999 using xda app-developers app

Alternative to 11W29+

Guys i came up with an idea
to change the kernel
by rewriting the kernel
i know this idea is crazy
but i just came up with this idea because im soo sick of using this stock roms stuck too much unlike the unlocked ones
im having 12W01 w8 mobile no wonder i bricked my phone twice
every one knows that we can modify the codes using rom manager so we just have to copy and paste whats in nAa kernel methods and implementations to stock tweaks
hope this will work
DEVELOPERS please consider

eh? explai better? you wanna unlock the bootloader with kernel for install kernel? ._.

its like this after 11W29+ they have blocked the kernel right
but still with using tools we can modify the running methods and implement new
so as i was trying to say it has to work if we replace the whole nAa Kernel methods and implementations to stock the whole bunch with out removing the kernel files

I dont think you can mod it whitout flashing it again...
Sent from my X8 using xda app-developers app

eh, nice idea bro!
but still, i don't think it could be possible without unlocked bootloader and trying it may brick your phone again as u need to probably reflash it, as said by Lukenda too...
good luck if you wanna try it. :good:
fingers crossed :fingers-crossed:

Do you mean something like this? I don't know if it works on X8 but with this thing we could be able to "install" custom kernels on devices with locked bootloader.

fifo171 said:
Do you mean something like this? I don't know if it works on X8 but with this thing we could be able to "install" custom kernels on devices with locked bootloader.
Click to expand...
Click to collapse
That could work. But i think the op is talking about modifying the kernel the phone is on as opposed to running a kernel on top of what's already there. At least that's how i understood the guide...
Sent from my rooted tomato using xda app

@OP : As long as the bootloader is locked, you can modify all the kernels you want, but it still won't be flashable to our phones.

untill your bootloader locked you cant flash any kernel mod into your device :'(

rohin he means to say to make changes in the stock kernel present in the phone some how and not flash new kernel...
it might work if some developer works on it....like alfsamsung and nobodyatall coming together and do it?
aZuZus method might be some help.. may be cwm flashable kernel? but that would require unlocked bootloader too.

CnC-ROCK said:
rohin he means to say to make changes in the stock kernel present in the phone some how and not flash new kernel...
it might work if some developer works on it....like alfsamsung and nobodyatall coming together and do it?
aZuZus method might be some help.. may be cwm flashable kernel? but that would require unlocked bootloader too.
Click to expand...
Click to collapse
To tamper with even the stock kernel, the bootloader needs to be unlocked. It's like trying to edit a stock rom (2.1 like Matej2010) without root. It's impossible.

Are you sure it won't work on locked BL? Then how is it possible that with kexec method X10 users can run custom kernels with locked BL? AFAIK they use the kexec to unload stock kernel and load custom kernel (for example like doixanhs DT module - it unloads the stock screen driver and loads the modified one. I think that kexec does the same with the whole kernel).

Provided you can load/unload the whole kernel w/o f*cking the system up

RohinZaraki said:
Provided you can load/unload the whole kernel w/o f*cking the system up
Click to expand...
Click to collapse
i suppose that if x10minipro can do it then so can x8

Yeah, maybe it's possible. Isn't here anyone to so that willingly?
Sent from my MANGO using Tapatalk2

Infact idea is working on the Samsung Galaxy S3 whereby Kexec is loading and selecting the boot from the recovery partition
But then we does need figure out a way to enable the system to boot from different partition.
hell of a work to rewrite script

Somebody should ask nAa and dx,they should know the answer
Sent from my X8 using xda app-developers app

@all azuzu's SBoot tool will make use of the kexec module. A kernel with a kexec module does not necessarily need an unlocked bootloader. It will (AFAIK) load up the new kernel for debugging over the existing stock kernel. We won't see such a kernel soon but that soon doesn't necessarily mean never.

Can we run 2 kernel om 2 different roms,like multibooting them? That way would be possible..
Sent from my X8 using Tapatalk 2

Lukenda said:
Can we run 2 kernel om 2 different roms,like multibooting them? That way would be possible..
Sent from my X8 using Tapatalk 2
Click to expand...
Click to collapse
Huh? Really explain what you mean and give an example if you can.

Custom ROM/recovery/... vs Stock

Hey there, I have been flashing my HTC Desire HD for a long time with different ROMs. I found it kinda annoying to always check certain websites for new updates, manually download and flash them just to find out that half of the stuff was buggy.
Now I got the Nexus 4. I loved the idea of having fast OTA updates. But now I want to flash a new kernel.. which means I got to install a custom recovery. But then OTA will not work anymore.
So I wonder:
Should I stay with
CWM + Stock ROM + Custom Kernel (no OTA update but no problem with buggy custom ROMs)
CWM + Custom ROM + Custom Kernel
Everything stock
Cyanogenmod is nice but for me it doesn't have any big advantages over stock 4.2 ? So I really wonder what you guys would recommend? What are your reasons to do a "certain setup" ?
Thanks

You don't need a custom recovery to flash a kernel.
It can be flashed with fastboot leaving everything else stock.
You still wouldn't be able to install the OTA without flashing the stock kernel again though.

Oh crap.. so as soon as I change ANYTHING... no OTA updates anymore
Hmm... I guess I will stay with custom kernel + flashing stock ROM then :/ Is there any way to automatically check for updates tho?
Thanks

zakazak said:
Oh crap.. so as soon as I change ANYTHING... no OTA updates anymore
Hmm... I guess I will stay with custom kernel + flashing stock ROM then :/ Is there any way to automatically check for updates tho?
Thanks
Click to expand...
Click to collapse
Yeah you will get the notification and it will try to install but it will fail and reboot if you aren't 100% stock.
Sent from my Nexus 7 using xda premium

Go with TWRP instead of cwm
Sent from my Nexus 4 using xda premium

calanizzle said:
Go with TWRP instead of cwm
Sent from my Nexus 4 using xda premium
Click to expand...
Click to collapse
+1, TWRP is great :highfive:

TWRP is the way to go!

But then I have another problem (well I already have it but..):
I would like to use ROMmanager.. after all it might be able to check for rom updates & flash them "automatically" (stock + custom?). I am not sure if it could also check for kernel updates?
Anyway, it seems to work only with CWM ? Altough it doesn't seem the already installed CWM on my Nexus 4 :S

Anyone?

I would never use ROM manager. Not a good program. Use a custom recovery, and if you want lots of customisation then I would recommend AOKP Rom as it is just as fast and stable as the stock ROM but with a whole host of customisation options.
Beauty of this phone is that you can go back to complete bone stock with no issues, I did, but missed all the customisation and put AOKP back on lol.

alright I uninstalled it. I just hoped for some "app" which could look for all kind of "custom" updates and install them automatically (kernerl,rom,...)

If you're interested in CM, I think delta CM will allow you download only the changes made to the project.
Also, why do people say to use TWRP instead of the more tried and true CWM? It seems to have a lot of sex appeal to some recently, and there doesn't seem to be a clear cut answer. Is there added functionality?

[Q] Nexus 4 Custom Kernel Help

Hi, I am a recent iPhone convert thanks to the Nexus 4. So obviously I am new to rooting, custom ROMS, and custom kernels. I am currently rooted and am running a recent CM 10.1 nightly. However, battery life isn't all that great.
A friend of mine told me that a custom kernel can drastically improve battery life without hurting performance. So here I am hoping that someone can help me. Can anyone recommend a good kernel that will improve battery life without hurting speed?
Also, what are the steps for installing a custom kernel? What about going back to stock in case I have to send my phone in for an RMA or something like that? Is that easy to do?
Thanks in advance for the help!

Try Franco or Harsh or trinity .
Custom kernels are more about under clocking a few things here and there to get best balance between performance and battery life thats and some tweaks which are generally inbuilt .
But tbh not all phone's are same what works for me and few others might not fetch u the same results, i've experienced this over my previous nexus device .
Some combo of ROM/kernel might work for u and not so well for other's i would say try out all the main stream kernels and some more if your'e feeling epxerimental give each kernel 2 to 5 days and see which u like the best.
Personally i've had good results with harsh kernel and franco and trinity .

berz said:
Try Franco or Harsh or trinity .
Custom kernels are more about under clocking a few things here and there to get best balance between performance and battery life thats and some tweaks which are generally inbuilt .
But tbh not all phone's are same what works for me and few others might not fetch u the same results, i've experienced this over my previous nexus device .
Some combo of ROM/kernel might work for u and not so well for other's i would say try out all the main stream kernels and some more if your'e feeling epxerimental give each kernel 2 to 5 days and see which u like the best.
Personally i've had good results with harsh kernel and franco and trinity .
Click to expand...
Click to collapse
Do you have one that you would suggest for a first time newbie? Also, what is the process for installing it and potentially uninstalling it back to stock?

Everything is easy to do. AS LONG AS YOU READ FIRST before doing anything You can start by reading the guides found here in the Nexus 4 General thread.
So far, the best for both performance and battery for me is Trinity kernel.
By the way, to install a custom kernel:
1. Install proper drivers for nexus 4 in your pc.
2. Unlock your bootloader.
3. Install custom recovery like CWM or TWRP Recovery
4. Start flashing your choice of kernels!
Sent from my Nexus 4 using xda premium

wtfshouldidonow said:
Everything is easy to do. AS LONG AS YOU READ FIRST before doing anything You can start by reading the guides found here in the Nexus 4 General thread.
So far, the best for both performance and battery for me is Trinity kernel.
By the way, to install a custom kernel:
1. Install proper drivers for nexus 4 in your pc.
2. Unlock your bootloader.
3. Install custom recovery like CWM or TWRP Recovery
4. Start flashing your choice of kernels!
Sent from my Nexus 4 using xda premium
Click to expand...
Click to collapse
Thanks for the advice! I am currently using CWM and have an unlocked boot loader. Is it as simple as downloading a zip, going into recovery, and installing the zip from "sd card"? If so, where can I find the zip for trinity? And how can I go back to stock in case something goes wrong?

There are post on xda and you could Google it. Just download it on your nexus and flash it
Sent from my Galaxy Nexus using xda app-developers app

strausd said:
Thanks for the advice! I am currently using CWM and have an unlocked boot loader. Is it as simple as downloading a zip, going into recovery, and installing the zip from "sd card"? If so, where can I find the zip for trinity? And how can I go back to stock in case something goes wrong?
Click to expand...
Click to collapse
If you want to be always safe and sure, then BEFORE flashing anything, go to CWM, choose backup and restore, then choose backup. That is called a nandroid backup. It might take a long time depending on how much apps you have. After the nandroid backup takes place, then you're free to flash the zip for trinity that you've downloaded.
I also suggest that you do backups often and delete old ones (you can delete old backups in the "backups and restore" part of CWM). So that incase anything goes wrong when you flash something, just go back to recovery mode, then restore your latest backup and you can undo your wrongs
Sent from my Nexus 4 using xda premium

wtfshouldidonow said:
If you want to be always safe and sure, then BEFORE flashing anything, go to CWM, choose backup and restore, then choose backup. That is called a nandroid backup. It might take a long time depending on how much apps you have. After the nandroid backup takes place, then you're free to flash the zip for trinity that you've downloaded.
I also suggest that you do backups often and delete old ones (you can delete old backups in the "backups and restore" part of CWM). So that incase anything goes wrong when you flash something, just go back to recovery mode, then restore your latest backup and you can undo your wrongs
Sent from my Nexus 4 using xda premium
Click to expand...
Click to collapse
So nandroid backups also backup the kernel?

strausd said:
So nandroid backups also backup the kernel?
Click to expand...
Click to collapse
bump. i also need to know the answer to this question.
EDIT: nvm found my answer, it backups the kernel too.
admins can delete this

imeem said:
bump. i also need to know the answer to this question.
Click to expand...
Click to collapse
nandroid backs up everything. it basically takes a snapshot of the state your device is in when you back it up, then restored your phone to exactly how it was before the backup.

Coming from HTC One S (and a whole lot of HTC family before that) and not having to deal with S-Off dilemma is a whole new free world for me (you can say i am institutionalized).
If I want to flash a rom and not the kernel included in it, can I just remove the boot.img file from the rom's zip and flash it? Or is that not a good idea?

justthefacts said:
Coming from HTC One S (and a whole lot of HTC family before that) and not having to deal with S-Off dilemma is a whole new free world for me (you can say i am institutionalized).
If I want to flash a rom and not the kernel included in it, can I just remove the boot.img file from the rom's zip and flash it? Or is that not a good idea?
Click to expand...
Click to collapse
no. you need to flash the whole zip. without a kernel, your device is an expensive brick. the kernel control pretty much everything and connects the hardware to the software. you can always flash another kernel after flashing the rom zip.

simms22 said:
no. you need to flash the whole zip. without a kernel, your device is an expensive brick. the kernel control pretty much everything and connects the hardware to the software. you can always flash another kernel after flashing the rom zip.
Click to expand...
Click to collapse
Thanks for the reply.
Are all kernels pretty much compatible with all roms?

justthefacts said:
Thanks for the reply.
Are all kernels pretty much compatible with all roms?
Click to expand...
Click to collapse
all nexus 4 kernels are compatible with all nexus 4 roms. if you flash a non nexus 4 kernel onto your nexus, you will most likely brick it.

Sounds great. This will be my first Nexus experience. Love this forum already. A very mature crowd.

Best Kernel for Stock (Non-Rooted)

I used to be an avid ROM flasher, changing ROMs daily on my old Moto X. Now that I'm using Android Pay religiously I need to keep my phone non-rooted, but would still like to run a custom kernel. I have been looking at FrancoKernel and ElementalX (sp?), but not sure what is best for the stock ROM without any tweaking (as most kernel tweaking apps need root). What's the community think?

grimez said:
I used to be an avid ROM flasher, changing ROMs daily on my old Moto X. Now that I'm using Android Pay religiously I need to keep my phone non-rooted, but would still like to run a custom kernel. I have been looking at FrancoKernel and ElementalX (sp?), but not sure what is best for the stock ROM without any tweaking (as most kernel tweaking apps need root). What's the community think?
Click to expand...
Click to collapse
Franco kernel
Flash it forget it
Cheers

I would also say Franco...

Never used Franco so I cannot comment on it. I use ElementalX, stock, rooted and it works awesome.
Sent from my Nexus 6P using XDA-Developers mobile app

Got Franco's kernel flashed with TWRP as recovery and everything else stock. Can already see battery life improvement, can't wait to see how it compares in the long run.

I hate using Franco Kernel.
For some reason everytime I use it I get more battery life then I should, and everything works faster than stock. I don't plug in my phone more than I have to. It's just the worst kernel out there if you want low OST and crashes.

Didn't think that you can replace boot.img on an uprooted phone.

grimez said:
I used to be an avid ROM flasher, changing ROMs daily on my old Moto X. Now that I'm using Android Pay religiously I need to keep my phone non-rooted, but would still like to run a custom kernel. I have been looking at FrancoKernel and ElementalX (sp?), but not sure what is best for the stock ROM without any tweaking (as most kernel tweaking apps need root). What's the community think?
Click to expand...
Click to collapse
I'm rooted with custom ROM and systemless root and Android Pay works 100%. Can add cards and pay at terminals without issue.
Just a little FYI.
Sent from my Nexus 6P using Tapatalk

Can we change the kernel if not rooted? If yes, can you share the procedure?

GroovyGeek said:
Didn't think that you can replace boot.img on an uprooted phone.
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Click to collapse
dharish said:
Can we change the kernel if not rooted? If yes, can you share the procedure?
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Click to collapse
Root has nothing to do with the ability to install a kernel. All that's required is TWRP recovery, which in turn requires an unlocked bootloader.
http://forum.xda-developers.com/nexus-6p/general/guides-how-to-guides-beginners-t3206928