vndk

[sanketmr121]

can someone explain what is vndk and which gsi to download for which phone ( architecture wise).
getting confused by so many new terms in android 11 gsi.

[kannony]

@sanketmr121 I believe VNDK and Binder64 are reverse-compatibility modules for phones that were upgraded from Android 8.0 or 8.1. There's mention of them in the documentation for GSI ROMs.

I think most people do not need them.

[sanketmr121]

Thanks, that helped.
Just to be sure, I have Samsung Galaxy J6 which was shippped with android 8, so i need to flash a GSI with VNDK module, Right ?

[kannony]

I do not know for certain whether that's the right image for the J6. As long as you do a full backup, you limit the risk of having to reinstall everything. VNDK stands for (I think) Vendor Native Development Kit and it has to do with how your manufacturer set up the default ROM on your phone. When they set it up for Android 8.0 or 8.1, it can have dependencies that are required in the image that you install.

The J6 uses a 64-bit processor so it probably doesn't need Binder64, which is for running 32-bit on 64-bit ARMv8 processors.

IIRC, A-B images are for devices upgraded from Android 9 and above. And the A-image is for Android 8. But I'm not sure about that. I do not know whether the A-B partition images are universal but the name suggests that it is.

The best course of action is to make a full backup and try the images in order of how likely they'll work on your system.

It's super important that you read the documentation. Here's a quote from the docs:

The most common supported use case is #2, where the legacy GSIs support devices running >Android 8.1 that were built with BOARD_VNDK_VERSION set to current.

Use case 0 and 1 are not supported by "GSI legacy" according to the documentation. Since the J6 was upgradeable to Android 10, it might be possible to use the "system-roar-arm64-ab-gapps.img.xz" GSI ROM, but I do not know for certain. You absolutely need to do a full backup and be prepared for the possibility that something will go wrong.

[sanketmr121]

Thanks for alll this information, cleared many doubts.

[kannony]

Oh, one more thing: in the GSI documentation it says A-B images are for legacy (upgraded from 8.0) and that A-images are for Android-10 compatible devices (non legacy).

However, I read the opposite about Phhusson's GSI ROM from someone who had asked the question much earlier. (A-B was for Android 10 compatible devices and A-images were for Android 8 devices). It's very confusing.

I am using an A-B image on an Android-10 compatible device and it works fine though.

[sanketmr121]

Tried few gsi and all give this error "failed to mount /system_root invalid argument". Found out it has something to do with dynamic partition, Any help ?

[sanketmr121]

what is reinstalling root, how to do it ?

[kannony]

https://www.techradar.com/how-to/how-to-root-your-android-phone-using-windows-10-and-twrp-recovery

I don't think it will help, but it's worth trying.

[kannony]

Also IIRC, TWRP has a reinstall root option.

[sanketmr121]

Havoc OS android 11 gsi booted succesfuly on first try itself, none additional steps required.

[rajshekhar99]

Try vndklite version of gsi, they have r/w access.