I've patched up the stock Huawei camera APK that's here so that you can access the photo gallery directly from the camera without having to bounce back out.
Technical details: There were a few animation resources using an easing function only defined in EMUI, which caused the whole mess to break. (That's why hitting the gallery icon made it look like everything stopped, and double-tapping Recents would cause the system to go to the gallery.) I fixed it by copying a different animation function into it's place.
I was trying to fix video recording as well - not there yet, but it looks like I did enable the panorama function in the process, and I was able to use it. Extra libs were brought in from the Mate 9 system image (8.0.0.366, US - C567).
Install: This is an update of the Magisk module at the top of the thread. Go to Magisk Manager, add this module. Reboot. Profit.
To get the Panorama function working with this, you've got to force HwCamera2 to run using armeabi-v7a, which I haven't figured out except for, using adb:
Code:
adb pull /system/priv-app/HwCamera2/HwCamera2.apk .
adb install --abi armeabi-v7a -r HwCamera2.apk
Open the camera app. It'll FC, that's fine. Go to App Info, remove all updates. For whatever the reason, the app now uses 32-bit libs, not 64-bit, and so the panorama module and a few others are available.
Edit: So, it's because the package manager remembers a forced abi setting. I've got a patch to that effect that I'll be dropping eventually with some other bug fixes.