Flutter debug Apk decompile to get the source code

Question

I have lost the source code of my flutter application due to drive corruption, but I have my debug.apk in my android phone. How can I decompile the Flutter apk to get source code? I have tried decompiling it using decompilers but it is not giving my source code as the Flutter source code is in Dart language.

Answer 1

If your debug.apk is in debug mode then you can use apktool in order to extract the components of the apk (I'm using the word extracting since apk is a zip file).

Flutter, in debug mode, keeps the source code (with comments!) in the file kernel_blob.bin. Thus, using the following command should help you extract the code into a file:

strings /path/to/extracted/apk/assets/flutter_assets/kernel_blob.bin > extracted_code.dart

Please, pay attention - You'll need to clean 'extracted_code.dart', from irrelevant/garbage strings.

Try to search strings like "dart", "import", "void" and other keywords in 'extracted_code.dart', it will help you find the code itself.

Here's an example from my Ubuntu:

If the apk is compiled in "release" mode, extracting the code will be much harder, since the code is compiled into isolate_snapshot_instr file, which is not a raw arm assembly, and is only deserialized using the Flutter engine in run-time. You can read more about it here