14
votes
Accepted
Is kernel mode of operating system and root permissions in android same thing?
Root permissions and kernel mode are not the same thing. Programs with root access can access part of the kernel, but root is not the kernel itself.
The Android (and Linux) user model has a set of ...
- 633
12
votes
Accepted
How can I enable last_kmsg?
Back in 2012, /proc/last_kmsg (1) used to be a dump of kernel console messages, exported after reboots by Android's ram_console functionality (CONFIG_ANDROID_RAM_CONSOLE), which used persistent_ram (...
- 19.9k
10
votes
Accepted
How to make Ethernet work on Android over OTG?
There is a long list of Ethernet related questions but none has a comprehensive answer covering all aspects. I'm generalizing your question in order to share my knowledge on this.
This is what you ...
- 19.9k
9
votes
What is the difference between the Linux Kernel and the Android Kernel?
I think this Android Source is a great documentation for understanding it.
And here is a list of changes done from mainline kernel for android kernel 4.14.
The largest features include:
19.8% ...
- 189
9
votes
Accepted
Is it possible to flash a boot.img kernel with TWRP?
Boot into TWRP, select Install and follow the screenshots for the rest.
(Click image to enlarge)
It's not a problem for TWRP to which ROM your particular kernel belongs. The size should not be ...
- 24.9k
9
votes
Backup/dump kernel image without root or twrp/cwm
It is possible to dump device partitions without root or custom recovery - if your device has "fastboot" mode and is boot unlocked. I'm not going to describe unlocking the boot loader, but with a ...
- 191
8
votes
Accepted
Why does Android differ so much from Linux?
Why didn't Google just take a Linux distribution ... and create a desktop environment for touchscreens?
Because they didn't want to create a desktop environment for touchscreens: they wanted to ...
- 34.8k
8
votes
Accepted
Booting kernel from fastboot
When you use fastboot boot FILE.img, the image is downloaded and written into the RAM and than the normal procedure to boot a boot.img is followed. No changes to any partition takes place.
If the ...
- 24.9k
8
votes
Accepted
Backup/dump kernel image (and full ROM) without root for Mediatek Devices
To answer my own question!
Warning, in some very rare cases this doesn't work or could be dangerous. For example, Amazon Fire devices refuse to communicate with these tools despite being MediaTek. ...
- 988
6
votes
Accepted
What happens if you install another phone's kernel on yours?
At a simple level, the effects would be catastrophic. The system wouldn't boot, and you would probably hard-brick OR super-brick. Kernels are the direct system for managing communication between ...
- 1,731
6
votes
Accepted
Is it possible to extract the kernel and device tree from a rom?
If it was that easy then we'd have custom ROMs in no time for every phone on the planet.
What's on our phone are compiled, it's basically impossible to decompile them (modern decompilers are not as ...
- 9,524
6
votes
Accepted
What is needed to run ELF binaries compiled from android APKs? (understanding android internals)
What is needed to run ELF binaries compiled from Android APKs?
A simple hello world app which does nothing except printing Hello World! (no animations, no sounds, no menus), running on Android 9 ...
- 19.9k
5
votes
Accepted
Building ROMs & Kernels?
1) Building in Android could mean:
- building a deliverable in the android build tree
- building a deliverable on an android platform having build tools installed
- building the AOSP (Android ...
- 129
5
votes
Accepted
Can IMEI number of a device really be changed
IMEI is an baseband identifier so it's stored on non-writable memory. There are two IMEIs actually - display and hardware. It's possible to change the display IMEI on rooted devices, but no way to ...
- 191
5
votes
Accepted
CPU-Z shows 8 cores, but 4 of them are stopped
Is there any way of activating all cores?
You can't.
The hardware is not designed to have all 8 cores active. The reason for this is that this Octacore CPU is actually based on big.LITTLE technology,...
- 19.1k
5
votes
Where are kernel modules installed?
There are two ways Linux kernel modules are built: 1. as a part of kernel executable binary (compressed image) i.e. with CONFIG_*=y options at build time, or 2. as separate kernel object (.ko) files ...
- 19.9k
4
votes
What is the difference between: Rooting, Jailbreaking, ROM, Mod, etc.?
TL;DR version:
Unlocking the bootloader
The initial program when you boot is the bootloader. If "locked" it may: 1) block attempts at flashing 2) refuse to boot the phone if something unauthorized ...
4
votes
Accepted
Can system apps be enabled/disabled directly from the filesystem?
Whether an app is enabled or disabled is stored in a single file /data/system/users/0/package-restrictions.xml.
I took the following steps to re-enable the Google App and solve my bootloop problem:
...
- 444
4
votes
Accepted
Application Sandboxing in Android
Every single application that is installed on your phone, gets a UID.
It is a number that Android uses to identify the apps so it can check from what app commands are executed and check the ...
- 2,682
4
votes
How can /proc/sys values be changed at boot (sysctl.conf does this on normal Linuxes)?
Use init's write command in /init.rc or any other .rc file. You may also create your own:
# /system/etc/init/custom.rc
on property:sys.boot_completed=1
write /proc/sys/kernel/hostname MyDroid
...
- 19.9k
4
votes
Accepted
SELinux permissive kernel - is it a security risk?
SELinux is a security framework which restricts (kernel and userspace) processes within their domains according to defined policy. So the ultimate goal is to load a working policy, label filesystems ...
- 19.9k
4
votes
Accepted
Native Linux on Android's SOCs
The main reason:
There is no revenue-generating stream for Linux on smartphones in comparison to Android.
Technical reasons, which can't be solved without heavy investments
Just porting Linux to SoC ...
- 156
3
votes
Accepted
What does the ROM files (FACTORYFS, HIDDEN, CACHE, PARAM, etc.) mean?
From [INFO] What the ROM files mean
boot.bin This is the Primitive Bootloader. Seems to make some basic
initializations and finally loads the secondary bootloader.
Sbl.bin The Secondary ...
- 200
3
votes
Accepted
Can I flash a custom ROM and a separate custom kernel after?
Yes, flashing a kernel is mostly safe. The worst thing that could happen would be a boot loop aka soft brick, which can be fixed by flashing another, proper kernel.
Remember that the kernel in your ...
- 4,052
3
votes
Accepted
Why isn't Android using kernel v4+?
Google's Android specific features were not included in the mainline Linux development. So they took the then LTS branch and added their own code.
Android does not use or include the native GNU C Lib, ...
- 174
3
votes
How can I find the name of the Kernel and its version that is running in my phone?
Unless Marshmallow has some unnecessary native changes, you should be able to see the kernel version in many Android releases from Settings → About phone.
(Click image to enlarge)
A command ...
- 24.9k
3
votes
What linux distribution is Android based on?
It's a modified Linux kernel plus modified libraries designed to run on a closed source architecture. The GUI is its own thing with no source-able materials, also partially why Google spent billions ...
- 31
3
votes
How can I check if a device is booted into safe mode from adb?
Aha! This'll do the trick! Android's dumpsys display command:
$ adb shell dumpsys display|grep mSafeMode
mSafeMode=true
- 440
3
votes
Accepted
How to brick android
You can easily root the phone (or do this in a working recovery) then run the following command in a shell:
dd if=/dev/zero of=/dev/mmcblk0 bs=1M count=1
Do note that unless you destroy a piece of ...
- 7,666
3
votes
Where to find information about WiFi connectivity of the device?
You can use various Wifi/network analysis apps from Play Store to get some of the information you're looking for. I suggest IP Tools. In its default screen/view, you would get to see following ...
- 24.9k
Only top scored, non community-wiki answers of a minimum length are eligible