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DiaKEM / dexcom-g7-apk-patcher

Dexcom G7 .apk patcher | ✅ AAPS Broadcasting ✅ Disable compatibility checks ✅ Enable Screenshots ✅ Decrease required android version
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android-aps dexcom dexcom-g7 reverse-engineering

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☢️ Dexcom G7 APK-Patcher 🧪

Build your own android based Dexcom G7.apk with some sugar on it.

ALL INFORMATION AND OFFERED RESOURCES ARE HIGHLY EXPERIMENTAL AND NOT TESTED. USE AT YOUR OWN RISK!

Dexcom G7 Experience DB

During exchange in our Discord we realized that Dexcom G7 has still significant problems in terms of reliability and stability. Many people are complaining about bad accuracy or permanent signal losses.

To collect these important information at a central place the community decided to create a dedicated database based on a simple Google Form and evaluate this data to identify patterns which lead to these problems.

Everybody is welcome to contribute. As soon as we have enough data we will publish the results to make it accessible for everyone.

Share your experience

Get help or share your experience

Join us on Discord

This is a very young project and therefore you might have questions or are facing problems during the setup. If you need help at some point you can ask for on Discord or just open a new ticket here in GitHub.

It would be also nice if you can share your positive experiences with others and provide some insights which setup you are running and how stable it is.

Available patches

✅ AAPS Broadcasting

✅ Disable Dexcom compatibility check

✅ Decrease required android version

✅ Enable Screenshots

⏬ Download

Sorry 😕 - unfortunately it is not legal to offer pre-built APKs but offer software which patches software 🤯. Just follow the instructions to patch a stock .apk.

Introduction

Dexcom G7 APK-Patcher is a simple tool which allows you to modify the official .apk-file.

There were also similar approaches for the G6 .apk which offered the same capability. If you are interested you can just check it here.

Modifications

AndroidAPS Broadcasting

This mod allows you to transfer your Dexcom G7 data to AndroidAPS and also supports backfilling.

Requirements

You will have to install a specific AndroidAPS version which supports G7 integration: https://github.com/DiaKEM/dexcom-g7-aaps

Decrease required android version

This mod just lowers the minimum and targeted android sdk version. Unfortunately this does not mean that the app will run on older devices without any troubles but you can give it a try and check it on your own.

Disable compatibility check

This mod bypasses the compatibility check by hiding the own device information and setting it to static values. A working combination was Google Pixel 4.

The corresponding diff looks like this:

Enable Screenshots

This small mod disables WindowManager.LayoutParams.FLAG_SECURE to enable screenshots in the application.

Known issues

Sensor readings during sensor errors and warm up time

Actually the patched app is not able to fully determine if the sensor is fully applicable. Because of this bug it will send values during:

Data Smoothing

As you might know as Looper and G7 user there is no data smoothing included in G7 at all. Dexcom has no statement about the G7 specifically but regarding G6 which might be still valid from their side: https://www.dexcom.com/en-us/faqs/why-does-past-cgm-data-look-different-from-past-data-on-receiver-and-follow-app

To overcome this issue @blaqone adviced to use smoothing directly in AndroidAPS and here we go: https://github.com/nightscout/AndroidAPS/pull/2141. This nice PR implements not only smoothing but also backward smoothing and guarantees nice interpretable data.

Please note that there is also an alternative approach with XDrip+ as middleware between Dexcom G7 and AAPS to just achieve the same. AS I UNDERSTOOD the only disadvantage with XDrip+ is its disability of backfilling data and missing SMBs in AAPS

Server Error on disclaimer page

Some users are facing a prominent Server error popup in the disclaimer step which prevents them to pass:

If you have the same problem it could be that you have an Ad Blocker installed. Please define an exception for the Dexcom app or totally uninstall the Ad Blocker.

How to patch?

Requirements

:warning: The patcher is actually only fully compatible with Linux / Unix operating systems or by using Docker or WSL on Windows. Unfortunately apktool can generate different filenames on Windows OS which makes the application of the modifications impossible. Please use the patcher only on Linux / Unix operating systems to ensure correct results.

The patcher will come with its own tools and does not require any high level dependencies actualy. But we need:

drawing Build

:warning: If you are using Windows the patcher will not work. As an alternative, you can use Docker or WSL.

After installing all requirements you can proceed as following:

Docker

To simplify the patching process `@rICTx-T1D introduced a basic docker setup. You can use it on any OS which can host Docker or equal compatible container engine. The CPU-architecture must x86/64 because some libraries need them.

To build on Linux/Unix you can just execute ./docker-build.sh which will create docker.patched.apk in your cwd.

Windows

If you want to patch under Windows, you have to download and install Ubuntu WSL. Afterwards you should be able to execute bin/docker-build.sh inside your WSL.

Make sure you disable automatic conversion of line endings in Git before cloning this repository from Windows:

git config --global core.autocrlf false

Reverse Engineering

The following section describes the toolset and development flow i am using. It should serve only as inspiration. I am sure that better tools and flows exists.

After modifications you can just run bin/dev-build.sh. This will rebuild the source, package it and also add the signature. Finally the Dexcom app will be reinstalled on your emulator/device to reflect the changes.

Troubleshoot

If you face any problems with the patched .apk especially in the broadcasting procedure it would be great if you can also provide logcat logs. This logs will simplify the analysis of such procedure drastically and also speed up the creation of solutions.

How to retrieve logcat logs?

Logcat can be accessed on any android phone without any modifications like ´rooting´ or something else. For this purpose i prefere Logcat Reader, a lightweight and simple logcat reader.

I can strongly advise you to increase parameter "Max recent logs to keep in memory" in settings to maximum ´250.000.000´. This will guarantee that older entries are not overwritten and you are able to retrieve also historical data.

To only filter for dexcom related log messages you can click on the magnifier and search for ´com.dexcom.g7´:

Finally you can save the logs and attach it to your GitHub issue by clicking the three dots in the upper right corner and click ´Save´.

Contributing

Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are greatly appreciated.

If you have a suggestion that would make this better, please fork the repo and create a pull request. You can also simply open an issue with the tag "enhancement". Don't forget to give the project a star! Thanks again!

License

Distributed under the MIT License.

Contact

Selcuk Kekec

E-mail: khskekec@gmail.com