MVV-app crashing on GrapheneOS

MattD

Hi there,
i switched to a Pixel 7 and installed grapheneos yesterday, coming from years of using Apple. Everything is working fine but one App is always crashing. Google services are installed and i even reinstalled them multiple times. I only have one profile on the device. I already enabled Exploit protection compability mode and the app also has network and sensor permissions.

The App is called: MVV muenchen
https://play.google.com/store/apps/details?id=com.mdv.companion

It's for my online train ticket which I need on a daily basis.

Thanks in advance for any help!

matchboxbananasynergy

MattD Hey there. I've been testing this out on my end and getting the same results, unfortunately.

When I tap on the app, it crashes soon after, with no crash log or anything of the sort.

This is on a user profile with Sandboxed Google Play installed through Aurora Store. Did you also install it through Aurora Store? If so, could you try installing it through Play Store itself? Sometimes that matters.

I also tried the following:

Made sure native code debugging in Settings > Security was enabled.
Disabled secure app spawning just in case.
Tried Exploit Protection Compatibility Mode, which means it's unlikely to be a memory corruption bug.

Let me know how it goes with the Play Store, and we can look further into it.

MattD

matchboxbananasynergy
Hi,
I installed it on aurora and on google play with the same results. I also tried it with the settings you mentioned but sadly it doesn't work. :(

matchboxbananasynergy

MattD The next step might be an inconvenient one, I'm afraid, but it would make sense to see if the app functions fine on Android 13 Stock OS.

There have been a few instances where an app was misbehaving and it turned out that it wasn't GrapheneOS-specific at all in the end...

MattD

matchboxbananasynergy the app works perfectly fine on stock android

Beerman

Yes, I can't get this app to work either. No matter what I do..

I searched a little bit in the reviews, but I cannot find someone complaining about crashes. (But they're complaining about much other stuff.... ;-) )

MattD

Beerman i know the app isnt the best but it's the only app on which i can buy the online ticket for my daily commute (train/bus) so i really need it :/

sugseg52

For a short-term solution, even thought it's not as good as using the native app: You could use Transportr app. It covers all Germany and when I was visiting Munich it covered the network in Munich quite good.

MattD

sugseg52 sadly this doesn't help me as i have my monthly ticket on the MVV App which i need in order to use the train/bus.

matchboxbananasynergy

MattD Of course this isn't a solution, but do they allow you to do that through their website, or do you have to use their app?

Beerman

MattD

Maybe it´s possible to you to switch to one of these 2 apps, where you can buy tickets for Munich and the surrounding area:
https://play.google.com/store/apps/details?id=de.swm.mvgfahrinfo.muenchen
https://play.google.com/store/apps/details?id=de.hafas.android.sbm

The frst one, I´m using myself. The second one, I tested and seems to be working.

matchboxbananasynergy

Is there any way to find out why the app crashes? Maybe we can learn from it for other apps how to debug in such cases and it could be that other apps don't work for the same reason.

MattD

matchboxbananasynergy only app is supported 🥲

matchboxbananasynergy

@MattD Would it be possible to reach out to them and ask them if they use SafetyNet/Play Integrity API? If they do, this would be why the app refuses to run on GrapheneOS...

At that point, they'd either have to stop doing that, or specifically whitelist GrapheneOS, for which the team provides a guide for developers to do so:

https://grapheneos.org/articles/attestation-compatibility-guide

MattD

matchboxbananasynergy good luck getting a response from them 🤣.

matchboxbananasynergy

For what it's worth, I did some more testing and tried their beta app, and I also tried in a profile without Sandboxed Google Play, just in case... no dice.

I'm leaning towards this being SafetyNet/Play Integrity API related, so you'll need to reach out to them and update us if they get back to you.

I know this is not ideal, but our hands are tied...

MattD

matchboxbananasynergy I found a solution for the next week (after next week I can buy the ticket in paper so i dont have to use the App), i installed the phone App on my MacBook (thanks to the M2 Chip I can install iPhone Apps trough the App Store) and now I can have the ticket on my Laptop xD. It's not the greatest solution but it works so I'm not complaining haha. Thank you anyway for taking your time for testing this for me!

shorty

Please mention what device you have if it doesn't work for you. I have just tested this on my Pixel 4a and the app seems to work. I don't have an account so I can't test further.

Owner profile
MVV-App versionCode: 602984013
Play services version: 22.41.13
- Play services permissions: Network, Sensors
Exploit protection compatibility mode: disabled
Settings > Security > Native code debugging: enabled
Settings > Security > Secure app spawning: disabled

matchboxbananasynergy

shorty Do you just generally have secure app spawning disabled, or did you find that it was needed for this app to run?

I've been testing on a Pixel 6, by the way.

Beerman

Yes, I tested again:

With "Secure app spawning: disabled" the app is running.

If I enable the option again, the app crashes.

(Pixel 7 Pro - No other option changed)

matchboxbananasynergy

Beerman Do you have the app on the owner profile? Also, have you restarted your device at all after disabling secure app spawning? If not, please do and let me know if it works still.

Finally, what's your Pixel model?