Custom ROM Troubleshooting Guide
Something went wrong? Don't panic. I've seen almost every possible issue, and most are fixable.
This guide covers the most common problems and their solutions.
Quick Diagnosis
What's Your Symptom?
| Symptom | Jump To |
|---|---|
| Phone won't boot past logo | Bootloop |
| No WiFi | WiFi Issues |
| No mobile data | Mobile Data |
| Camera not working | Camera Issues |
| Battery draining fast | Battery Drain |
| Apps crashing | App Issues |
| SafetyNet failing | SafetyNet |
| No sound | Audio Issues |
| Weird performance | Performance |
Bootloop
Phone stuck restarting or frozen on boot logo.
Causes
- Incompatible ROM for your device
- Missing firmware/vendor
- GApps issues
- Failed flash
Solutions
Solution 1: Boot to Recovery and Reflash
1. Force power off (hold power 10+ seconds)
2. Boot to recovery:
- Power + Volume Up (most devices)
3. In TWRP:
- Wipe → Advanced → Dalvik, System, Cache
- Flash ROM again
- Flash GApps (if using)
4. Reboot
Solution 2: Try Without GApps
GApps can cause bootloops:
1. Boot to recovery
2. Wipe as above
3. Flash ROM WITHOUT GApps
4. Reboot
5. If boots: GApps was problem (try different package)
Solution 3: Flash Different/Older ROM Version
1. Download known working version
2. Boot recovery
3. Clean flash
Solution 4: Check Firmware Requirements
ROM may need specific firmware
Check ROM's XDA thread
Flash matching firmware before ROM
WiFi Not Working
Quick Fixes
- Toggle WiFi off and on
- Airplane mode on/off
- Reboot device
Deeper Fixes
Firmware Mismatch (Most Common)
1. Check ROM requirements
2. Flash matching firmware
3. Reflash ROM
Wrong WiFi MAC (Shows 02:00:00:00:00:00)
1. Restore EFS backup (if available)
2. Or search XDA for MAC address fix for your device
Permission Issue (Android 12+)
Settings → Apps → Settings → Permissions
- Location: Allow
- Nearby devices: Allow
Full WiFi troubleshooting guide
No Mobile Data
Quick Checks
- SIM card properly inserted?
- Mobile data toggle enabled?
- APN settings correct?
Fixes
Set APN Manually
Settings → Network → Mobile network → Access Point Names
Add your carrier's APN (search "[carrier] APN settings")
Baseband Unknown?
If About phone shows "Unknown" baseband:
Flash matching firmware/modem
[Baseband fix guide](/guides/baseband-unknown)
Wrong ROM Variant
Some devices have regional variants:
Check ROM matches your exact model number
Example: SM-G950U vs SM-G950F require different builds
Camera Problems
Black Screen
1. Try different camera app
2. Install GCam port
3. Check if firmware matches
4. Clear camera app data
Crashes on Open
1. Clear camera app data
2. Try third-party camera
3. Check SELinux status:
- If changing to permissive fixes it, report to ROM developer
Auxiliary Cameras Not Working
1. Expected on many AOSP ROMs
2. Check ROM's known issues
3. Some ROMs need special config
Battery Drain
First 3 Days
Normal: Battery is worse while Android optimizes apps
Wait 3 days before judging.
After 3 Days
Check What's Draining
Settings → Battery → Battery usage
Look for unusual entries
Google Play Services High?
Install Universal GMS Doze (Magisk module)
Unknown Wakelocks?
Use Better Battery Stats (root) to identify
Quick Fixes
1. Disable location services when not needed
2. Restrict background for unused apps
3. Disable WiFi/BT scanning
4. Lower screen brightness
App Crashes
Single App Crashing
1. Clear app data: Settings → Apps → [App] → Clear Data
2. Reinstall app
3. Check for updates
Google Apps Crashing
Wrong GApps or incompatible version
1. Boot to recovery
2. Wipe → System, Dalvik
3. Flash ROM
4. Flash different GApps package (try Core or Basic)
All Apps Crashing
Possible system corruption
1. Boot recovery
2. Full clean flash of ROM
SafetyNet Failing
With Root (Magisk)
1. Update Magisk to latest version
2. Enable Zygisk
3. Install Play Integrity Fix module
4. Configure DenyList properly
5. Hide Magisk app
6. Reboot
Without Root
Unlocked bootloader still fails some checks:
1. Re-lock bootloader (ONLY on stock ROM!)
2. Or: Some apps just won't work with unlocked BL
Audio Problems
No Sound at All
1. Check volume (obvious but happens)
2. Reboot
3. Try Bluetooth audio (isolates speaker vs system issue)
Distorted/Crackling
1. Check audio profile settings
2. Disable audio enhancements
3. Try different ROM kernel
Calls Work But Media Doesn't
Check audio profiles/routes
Possibly mixer path issue - ROM-specific fix needed
Performance Issues
Lag After Flash
Normal for first few hours:
- ART optimization
- Indexing
- Learning usage patterns
After 24+ Hours:
1. Check battery stats for runaway apps
2. Disable animations:
Developer Options → All animation scales → 0.5x
3. Clear cache partition in recovery
4. Try different kernel
Random Freezes
1. Check for memory leaks (monitor RAM usage)
2. Try different ROM version
3. Try without certain apps
Recovery Issues
Can't Boot to Recovery
1. Use ADB: adb reboot recovery
2. Try different button combo
3. Reflash recovery via fastboot
Recovery Replaced by Stock
Boot directly to recovery after flashing
Flash Magisk or ROM before booting system
Can't Decrypt Storage
Use TWRP matching your Android version
Or: Format Data (erases everything)
Other Issues
Bluetooth Problems
1. Forget and re-pair devices
2. Clear Bluetooth app data
3. Check if others have same issue with ROM
GPS Not Working
1. Check if ROM supports GPS for your device
2. Firmware issues common cause
3. Try GPS fix modules (Magisk)
Fingerprint Not Working
1. Re-enroll fingerprints
2. Check if ROM supports your sensor
3. Firmware mismatch possible cause
When All Else Fails
Nuclear Option: Clean Flash
1. Factory reset in TWRP (Format Data)
2. Wipe System, Vendor, Cache, Dalvik
3. Flash fresh firmware
4. Flash fresh ROM
5. Start clean
Try Different ROM
Some ROMs work better on different devices:
1. Research alternatives on XDA
2. Read recent posts for issues
3. Try stable LineageOS if available
Return to Stock
When custom ROM life isn't working:
[Stock restore guide](/guides/restore-stock-rom)
Getting Help
Where to Ask
- ROM's Telegram/Discord group
- XDA device forum
- ROM's official support channels
What to Include
- Device model (exact variant)
- ROM name and version
- What you've already tried
- Logcat if possible: adb logcat > log.txt
Prevention Checklist
For future flashes:
[x] Read ROM requirements completely
[x] Download correct device variant
[x] Flash required firmware first
[x] Make TWRP backup before flashing
[x] Use recommended GApps
[x] Clean flash for major changes
Most issues have solutions. Don't give up too quickly - the community is helpful, and almost every problem has been solved before.
Keywords: custom rom troubleshooting, fix bootloop, rom problems, android flashing issues, custom rom help