There are times when you get into the more advanced root dealios, where you’re going to run into some problems. To these ends I’ve compiled here a list of some of the top issues I’ve run into and how to fix them. If you’ve got any root troubleshooting advice for the root community, feel free to add on in the comments section.
Since my experience is mostly with HTC devices, this will be pretty HTC centric, except for what’s added later by users.
WiFi doesn’t work after kernel install
A big problem when switching kernels seems to have been bad updater scripts or updater scripts that assume you have a completely unlocked device. It’s important to remember than an unlocked device is not the same as an S-OFF device.
A kernel install package may attempt to write to areas it’s not allowed to based on your current ROM.
WiFi not working is generally symptomatic of an installer that was unable to complete writing config files, or a kernel that’s incompatible with the ROM you’re using. Sometimes they just don’t play nice together.
Your first step in attempting to fix the kernel issue is to reflash the kernel. Depending on whether you’re S-OFF or simply unlocked you might need to use the fastboot method in order to push the kernel properly. You’ll need to see if your kernel is S-ON friendly.
If that doesn’t work use something like Flash Image GUI. Flash Image GUI does a wonderful job of putting things in the right place even if you’re S-ON.
If none of that succeeds you’ll want to try a different kernel.
Want to revert to old kernel but don’t know where to find it
If you’ve got the original installer for your ROM, you’re in luck. The easiest way is to grab Flash Image GUI, point it at the ROM install package, and have it extract and install the kernel for you. This way you know all the things will get put in the right place.
Alternately you can extract a file called boot.img and flash that through fastboot.
ADB shows device offline
You run adb devices and when your phone is connected it shows as offline. Unplugging it makes ADB show no devices.
The issue is you’re running an older adb from either an old install of the Android SDK or a toolkit that was produced with an older pre 4.x compatible ADB. You simply need to get a newer version that supports the new ADB security.
ADB won’t connect when device is in Android mode
Go to Settings > Developer options > check USB debugging.
Developer options not visible in settings
Go to Settings > About > Software information > More, and tap the build number a few times until it says you’re a developer. The menu should appear.
Application claims it can’t install root components even though root permission granted
I get this usually when I’m dealing with Battery Monitor Widget Pro, but it’s happened on a couple of other applications. You grant them Superuser access, then they report that they failed to install whatever component they need.
I’m not sure this is the end-all fix for these issues, but it’s worked for me.
Open up a terminal window in whatever terminal emulator app you have, type su and press return. Grant superuser to the terminal emulator window. Return to the other app, try the process again, it may work now. It does on BMW Pro every time.
Screen tearing occurs
Screen tearing means there’re lines and garbage on the screen. This happens a lot in early development ROMs that are ported from other systems. Best solution here is to wait for them to be fixed, but you can also do things to troubleshoot on your end like lower the GPU speed, disable hardware overlays, and muck around with options in the developer settings.
You can also use applications like GLTools if the tearing only happens on games to modify what the game is seeing. Unfortunately there’s not a solid, across-the-board fix for this.
Screen vulnerability to walls
Some root users have noticed that their phones develop a screen vulnerability when faced with a wall at high velocity. This can best be avoided by keeping a know-good ROM available for fallback when your bleeding edge ROM ticks you off.
Alternately an improved case can sometimes mitigate the underperforming ROM’s issues.
Flashed boot animation, old boot animation still there
Unfortunately there is no agreed upon standard across manufacturers and ROMs. If it didn’t work you’ll need to find out what the name of the boot animation is for your device and see if that’s copying.
Additionally, some devices are restricted and unable to access certain folders such as where the boot animation lives. This is most common on HTC devices where an S-ON device may be unlocked but forget about touching the folder you want in recovery.
System stuck in recovery
I had this happen with some misbehaving TWRP ports early on where they got stuck in an operation and failed to ever complete the operation. You can either connect to a computer and run adb reboot or hold power and volume up for 10 seconds or so until the device reboots.
Alternately, if you have a battery you can yank it, or wait until it eventually dies.
Switched recoveries, want to recover old nandroid data
So you’ve installed TWRP and have been running ClockworkMod most of your root life, or vice versa. You’ve discovered that the potentially lost love of your life’s text message from out of the blue to you didn’t make it to your new ROM and you absolutely need to get that nandroid back.
Couple of options here – the first is simply switching recoveries back to the old one for a one-time restore. There’s no damage done to your device swapping out recoveries, although you can look back and see some dire warnings a few years ago that there potentially were. It’s not the case any more. A recovery can be swapped in about 10 seconds, and swapped back out to the original in the same amount of time. If you’re feeling adventurous you can even swap between them if you want to take advantage of ClockworkMOD’s new backup schema, but TWRP works better on your device for flashing.
Alternately you can get an app like Nandroid Browser or Titanium Backup and just extract data from your old nandroids.
This list is far from complete and pretty HTC centric. Feel free to let me know what I missed and how to fix it in the comments. If it’s good I’ll add it up here and of course credit will be given. Also hopefully there’ll be some things I haven’t run across and how to fix them added.