Struck on boot an dm-verity corruption [solved]

[mithrandir]

After adding a magisk module on my Astro I got an endless "Smartphone wird gestartet" (Smartphone is starting in english). Tried to disable magisk in hope to recover (fastboot flash boot_a boot-mystock-v07.img), no change. Then I have testwise switched to slot b (fastboot --set-active=b), not booting at all. Then switched back to slot a, now I get a dm-verity corrupted error. When bypassing the dm-verity error with the power key the Astro is struck at the starting message "Smartphone wird gestartet".

Any idea how I could recover?

[ZimbiX]

That sucks.

I see your image file says V07. Were you not on V07b? It could just be that it's the wrong version.

It's not something I'm familiar with, but I don't think switching the active slot would work well - it's not just the boot partition that's used.

I'd try switching the active slot back and flashing the stock v07b boot image from the rooting wiki page.

You could also try to boot while holding a button to get Magisk to disable itself - see the Magisk FAQ. I haven't tried this on the Astro, but I've used it in the past on another device to resolve this.

Edit: I wrote instructions to remove the dm-verity corruption prompt/warning. Perhaps you need to do that again after a manual slot switch.

[mithrandir]

Thanks. Thank to your hints I got aware of shymegas / loopback7084s astro_super_tools. I think it really was V07, since I didn´t have the v7b on my harddisk. There is an adb server running, but I was not able to get in, maybe I didn´t permanently allow.

With the astro_super_tools and and mtk-client I have been able to download the current images from the phone. Then I added  setprop ro.adb.secure 0 to build.props in the system partition (had to free some space, there are sufficient unneeded apks...) and flashed it (super.img) with fastboot. (Details in astro_super_tools ReadMe). The wiki also was helpful.

Afterwards adb via USB was working and reading logcat was possible. In logcat output I have noticed an error mentioning com.google.android.gms which I then removed with pm uninstall com.google.android.gms. Suddenly the user interface started I was able to reinit magisk, for some reason it wanted to reinstall the manager app. Then I was able to remove some magisk modules I added some days before.

Great, the Astro is ressurected  . Still some stuff to do, lost my desktops, but that is not that important, at least I have lost no data. Tomorrow I will continue to solve the remaining problems, i.e. sync stuff not working anymore (due to gms). The device boots and I have root, so everything else should be fixable.

Thanks to all who helped with hints, here and in the matrix.