Install Custom Kernel on Android
Custom kernels are where serious Android tuning happens. While ROMs change what you see, kernels change how your hardware actually performs.
Fair warning: this is more advanced than ROM flashing. But if you want the absolute best from your device, kernels are where it's at.
What is a Kernel?
The kernel is the core of your operating system. It:
- Manages CPU frequency and governors
- Controls memory allocation
- Handles hardware communication
- Manages power states
- Runs device drivers
Think of it this way: ROM is the house, kernel is the foundation and electrical system.
Benefits of Custom Kernels
Performance
- Better CPU governors (how CPU scales)
- I/O schedulers optimized for flash storage
- Wake locks management
- GPU overclocking options
Battery Life
- Smarter doze mode
- Better deep sleep
- Power-efficient scheduling
- Aggressive idle states
Features
- Undervolting (same performance, less power)
- Overclocking (more power when needed)
- Sound enhancements
- Display calibration
- Wake gestures (double tap to wake)
Prerequisites
Before installing a custom kernel:
- Rooted device with Magisk
- Custom recovery (TWRP)
- Compatible kernel for your ROM/Android version
- Backup of current system (TWRP backup)
- Basic understanding of what kernels do
Critical: Kernels are ROM and Android version specific. Wrong kernel = bootloop.
Popular Custom Kernels
| Kernel | Known For | Devices |
|---|---|---|
| ElementalX | Balance + features | Multi-device |
| Franco Kernel | Performance + battery | Multi-device |
| blu_spark | Stability | OnePlus, Pixel |
| Kirisakura | Gaming focus | OnePlus, Pixel |
| arter97 | Battery life | Samsung |
| Sultan Kernel | Stability | OnePlus |
How to Choose
- Gaming: Look for GPU tweaks, high performance governors
- Battery: Look for power-saving features, undervolting
- Stability: Go with well-known, long-maintained kernels
- Features: Check feature list matches your needs
Step 1: Find Compatible Kernel
Where to Look
- XDA Forums: Device-specific subforum → Kernel section
- Kernel developer sites: Many have their own sites
- ROM developer recommendations: Often bundled or suggested
Compatibility Check
Verify before downloading:
- Android version matches (e.g., Android 14)
- ROM compatibility (some kernels are ROM-specific)
- Device codename matches
- Recent updates (abandoned kernels = security risk)
Step 2: Download Kernel
Kernels come as:
- Flashable ZIP (most common) - flash via TWRP
- IMG file - flash via fastboot
- AnyKernel3 format - modern packaging, flash via TWRP
Always download from official sources linked in XDA thread.
Step 3: Backup Current Kernel
Before flashing, backup your working boot image:
Via TWRP,
1. Boot to TWRP
2. Backup → Boot (check only boot)
3. Swipe to backup
4. Note backup location
Via ADB
adb shell
su
dd if=/dev/block/bootdevice/by-name/boot of=/sdcard/boot_backup.img
exit
adb pull /sdcard/boot_backup.img
Step 4: Flash Kernel
Method 1: TWRP (Recommended)
1. Copy kernel ZIP to phone storage
2. Boot to TWRP:
- Power off
- Hold Power + Volume Up
3. Install → Navigate to kernel ZIP
4. Swipe to flash
5. Reboot → System
Method 2: Fastboot
For .img kernels:
adb reboot bootloader
fastboot flash boot kernel.img
fastboot reboot
Method 3: Kernel Manager Apps
Some kernels support in-app flashing:
- FK Kernel Manager
- EX Kernel Manager
- SmartPack-Kernel Manager
1. Install manager app
2. Download kernel through app
3. Flash with one tap
4. Reboot
Step 5: Configure Kernel
After flashing, configure settings for your use case.
Using Kernel Manager App
Most popular: Franco Kernel Manager or EX Kernel Manager
Settings to explore:
- CPU Governor: How CPU scales frequency
- CPU Frequencies: Min/max speeds
- GPU Settings: Frequency, voltage
- I/O Scheduler: How storage is accessed
- Wake Gestures: If kernel supports
- Vibration Strength: Fine-tune haptics
- Sound Control: Volume, gain
Common Governors
| Governor | Description | Best For |
|---|---|---|
| schedutil | Default, balanced | Most users |
| interactive | Responsive | Daily use |
| ondemand | Quick scaling | Performance |
| conservative | Slow scaling | Battery |
| powersave | Minimum frequency | Extreme battery |
| performance | Maximum frequency | Benchmarks only |
Recommended Starting Points
Battery priority:
Governor: schedutil or conservative
CPU Max: 80-90% of maximum
GPU Max: 80% of maximum
I/O: noop or cfq
Performance priority:
Governor: performance or interactive
CPU Max: Maximum
GPU Max: Maximum
I/O: deadline or cfq
Balanced:
Governor: schedutil
CPU: Default limits
GPU: Default limits
I/O: cfq
Undervolting (Advanced)
Undervolting reduces voltage at each CPU frequency step, resulting in:
- Same performance
- Lower heat
- Better battery
- Potential stability issues if too aggressive
Safe Undervolting Process
1. Start conservative (-25mV)
2. Use phone normally for a day
3. If stable, reduce another -25mV
4. Repeat until instability occurs
5. Back off one step
6. Save profile
Warning: Too aggressive undervolting causes random reboots, freezes, and crashes. Always be able to recover.
Troubleshooting
Bootloop After Kernel Flash
1. Boot to TWRP (hold buttons during reboot)
2. Install → Navigate to kernel backup or stock kernel
3. Flash
4. Reboot
If no backup:
1. Boot to TWRP
2. Flash ROM again (kernel is included)
3. Reboot
Random Reboots
Causes:
- Unstable undervolt settings
- Aggressive overclock
- Incompatible kernel
Fix:
- Boot to TWRP
- Flash different kernel or stock
- If kernel settings are the issue, boot to recovery and reset kernel settings via file deletion
No WiFi/Audio/Camera
Wrong kernel for your device variant. Flash compatible kernel or return to stock kernel included with ROM.
Kernel Manager Shows Wrong Info
Some kernels don't expose all features to all managers. Try:
- EX Kernel Manager
- FK Kernel Manager
- SmartPack-Kernel Manager
Testing Your Kernel
Benchmarking
Apps to test performance:
- Geekbench 6: CPU benchmarks
- 3DMark: GPU benchmarks
- AnTuTu: Overall performance
- PCMark: Real-world usage
Battery Testing
Apps to monitor:
- AccuBattery: Battery health and usage
- GSam Battery Monitor: Detailed stats
- Better Battery Stats: Wake locks (requires root)
Stability Testing
- Use phone normally for 24 hours
- Run CPU stress tests
- Play demanding games
- Monitor for random reboots
KernelSU vs Magisk with Custom Kernels
Some kernels now support KernelSU, an alternative to Magisk:
| Feature | Magisk | KernelSU |
|---|---|---|
| Root method | Patching boot | Kernel-integrated |
| Module support | Extensive | Growing |
| SafetyNet | Via modules | Native support |
| Kernel requirement | Any | KernelSU-enabled |
If kernel supports KernelSU, you can choose. Most users still prefer Magisk for module availability.
Popular Kernel + ROM Combinations
Tested combinations from the community:
| ROM | Kernel | Experience |
|---|---|---|
| Pixel Experience | Stock | Stable, safe |
| LineageOS | Stock | Recommended |
| Evolution X | Kirisakura | Gaming boost |
| crDroid | Franco | Good balance |
| Any AOSP | ElementalX | Features galore |
My Personal Setup
What I run and why:
Device: [Device]
ROM: Evolution X
Kernel: Franco Kernel
Settings:
- Governor: schedutil
- CPU: Stock frequencies
- Undervolt: -50mV (tested stable)
- I/O: cfq
- Wake gestures: Enabled
Result:
- 15% better battery than stock kernel
- No performance loss
- Double-tap to wake is convenient
Summary
Installing custom kernel:
1. Find compatible kernel for your ROM/Android version
2. Backup current boot image
3. Flash via TWRP (safest method)
4. Configure using kernel manager app
5. Test stability for 24-48 hours
6. Fine-tune settings based on your usage
Custom kernels are the secret to squeezing every bit of performance and battery from your device. Start conservative, test thoroughly, and enjoy the gains.
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