How to modify system app? - Android Q&A, Help & Troubleshooting

Hi all,
I'm trying to comment out one line of code in system apk on car head unit.. Im using apktool to decompile and then compile again.
However I cant update the app, it says something like that app is persistent... System is Android 9, rooted.
If I replace apk in root system then I get corrupted android and need to do factory reset. Can someone help?

Related

[Q] Android App not installed

Okay so I am trying to reverse engineer an android app, whatever you want to call it. Anyways I get the apk, and I rename it as a .zip. I use the dextojar to change the classes.dex to a jar so I can use a decompiler to look at the code. I found what I wanted to change so I used a smali converter and changed the classes.dex to the smali files.. changed the smali to my liking then converted back to the classes.dex, put it back into the zip and then back to apk and the phone itself.
I have done this before, it has worked before... now no matter what app I do this to, it doesn't work? I tried on a nexus 5 and a 2013 nexus 7
Is it because of the android update? Any ideas would be helpful...
Thanks!

APP want Versionupdate after recompile and sign?! Need help!

Hello,
I have decompiled APK File, changed a picture and recompiled + installed it.
but now on starting the app i geht error message like "Software update - there is a new version in the playstore"
Is there any way to bypass this problem? i cant use the app because it wants a software update ( its the same version like in the playstore no update available )
I have already checked the .dll files if there are any codes checking modifying the APK but nothing found
hope you can help me !!

Help modifying an apk

Good day,
I need help on modifying an apk, its basically a game that can be dowloaded on playstore. I read alot in the forum and I saw this APK tool reverse engineering an app.
apktool. I already ask a question but maybe it's better to create a new thread that I can monitor..
Now. what I achieved now is that I can decompile the apk, edit some things like splash.png, values on strings.xml and few line on androidmanifest.xml. I tried to recompile it and I have done it with no problem. Now i have the modified apk. I signed it using apk signer and followed all the procedure with no error. I copied it to my phone and test run it but sadly it says "App not installed". I also tried using zip signer from playstore and got the same result.. I dont know where am I messing it. Please help thanks.
There is Windows app called Virtuos Ten Studio, designed to do exactly that - it works pretty well and makes the whole process much easier (no need to use cmd line at all if I remember correctly).

How would I debug an Android app to figure out how to inject my own images instead of the ones designated? Is there a tool to see "under the hood"?

What tools can I use to do that? I know how to do it with JS web apps, but I'm not sure how with an Android one. Can someone please give me a couple pointers? I don't need you to hold my hand. Just give me something to go off of as a start. I will read whatever you post.
Thank you
didymus said:
What tools can I use to do that? I know how to do it with JS web apps, but I'm not sure how with an Android one. Can someone please give me a couple pointers? I don't need you to hold my hand. Just give me something to go off of as a start. I will read whatever you post.
Thank you
Click to expand...
Click to collapse
First, are you trying to modify a system app or a user installed app? If it is a system app, it will probably require your device to be rooted in order to make your modifications and have it actually work.
You would need to use something like APKtool or some other kind of decompiler to unsign and decompile a copy of the apk file for the app. Then, when you find where the images are located in the decompiled file system, replace them, then recompile and resign the apk file and install the modified apk, reboot to recovery, wipe cache partition(but do not factory reset), then reboot the device.

Resign system application

Hi,
Hope someone would be able to give me some help\advice.
I have a system application and trying to install it onto another phone. The installation keeps failing.
How would I get this app resigned so it will install?
The phone that I am trying to install the apk on is a nexus 5 with a custom rom.
Any help would be appreciated.
Thanks
If your getting a error about it not being signed, you need to find a signed installation. You cant sign it yourself.
Thanks for the response.
So if I wanted to add a system app into a Rom before I flash the phone can that be done and how would I do it?
Thanks
All the system apps have to have a signing that matches that of /system/framework/framework-res.apk
The most radical solution is for you to resign everything with your own keys.

Categories

Resources