Decided I wanted to post some more notes:

Pixel Experience A11 GSI's stock Google file manager can't see files on my exFAT microsd, it just comes up as empty. Which in turn means I couldnt use the Storage Access Framework to select files stored there. Ever since A10, Google has put in place alot of restrictions in regards to storage. But 3rd party file managers read the contents just fine. So I downloaded Phh official A11 GSI and extracted DocumentsUI from system priv-app. And then manually copied the files to system priv-app in the running ROM, set correct permissions, reboot. Now there is Google's file manager, and the stock non-Google AOSP file manager. I just had to set the AOSP file manager as default, now selecting files via SAF works correctly and I'm able to see all files on the exFAT partition.

For measuring FPS in games I use PerfMon Plus. Can be found at: This requires root, but it shows the actual FPS, not just the refresh rate of the display. Besides FPS, it also displays some other useful info. If you give it the draw over apps permission, it can even run on top of whatever app is currently running. Great for real-time stats. Stock Samsung firmware has GPUWatch that does the same thing, but I don't think it will work on GSIs. All other apps/solutions I've tried claim to show the FPS, but in actuality they are only showing the refresh rate. Not the same thing. So, if you had your RR set to 120, these apps would mistakenly show this as your FPS.

I found a solution for Dolby Atmos too, and it even works with SELinux enforcing: Use the "Download" button in the top right of the page and select the latest release zip, flash in Magisk and reboot. Open the Dolby app and configure how you like. I tried another Atmos module from an XDA thread, but it caused a bootloop.

There are some Atmos test vids on YouTube that you can try to verify it's working. I can clearly hear certain sounds playing on the left side of my earbuds but not the other, and vice versa. The same applies with up/down directional audio. With plain old stereo audio, the audio would sound as if it's playing through both sides at the same time. This is very useful in the games I play, for things like determining the direction of footsteps, gunshots, vehicles.

As an alternative to Secure Folder on the stock ROM, you can use the Shelter v1.7 app from F-Droid. Tested by me and working fine on A11. It basically sets up a Work Profile that you can use to run certain apps in isolation. An app called Island by @oasisfeng may also work, but I haven't tested it. On stock firmware, I wasn't able to get either of these to work while rooted, SF was the only viable option.

And before I forget, handling the watchdog issue without root/custom kernel. TWRP is required for this, as well as a vndk/vndklite GSI that allows system to be remounted as read/write:

In TWRP, go to the Mounts settings tab, put a checkbox by all partitions (except USB storage). Then open the TWRP terminal. Type the following commands:

mount -o rw,remount /

mount -o rw,remount /system_root

echo "echo -n V > /dev/watchdog0" >> /system_root/system/bin/rw-system.sh

These are 3 separate commands, on separate lines. Just press the enter/return key after each one. You shouldnt receive any visible output for each, unless there is an error.

If you get an error, try checking the path of rw-sytem.sh file in TWRP file manager, then adjust the path accordingly. Reboot and see if you get any watchdog issues that would force the ROM to hard reset. It's also worth noting that recent Phh-based GSIs already handle watchdog1, but they apparently don't handle watchdog0.

For rooting with Magisk on A11 vendor:
Extract the boot.img.lz4 from the AP tar.md5 of whatever firmware you're using as a baseline (in other words, whatever stock firmware you were running before the GSI). 7-Zip zstd can be used in windows to extract the boot.img from this lz4 (regular 7-Zip version will give an error). Copy the boot.img to unrooted tab, patch the file with Magisk Manager. Copy the patched img file back to PC, compress it into a tar file with 7-Zip. Put the tab in download mode, flash the patched tar file with a recent version of Odin (will need to install most recent Samsung USB Driver if Odin doesn't detect the tab with a blue box in the upper left). You should hopefully be rooted now, you just need to install and open the Magisk Manager app and let it set up (ideally while connected to internet so it can fetch any needed files).

Next I'm working on getting ViperFX working, I want to see if it can peacefully coexist with the Dolby mod. Then I will probably move on to testing Android 12 GSIs.

Edit: Another issue I've noticed is that auto-brightness doesn't work, it just stays the same no matter what. It should be dynamically changing to take into account things like lighting conditions, but it doesn't from what I can tell. However, you can change brightness manually with the slider, no issues there. But it will just stay set to wherever you left it. Not sure how to address this, am hoping someone has ideas or a solution. 3rd party apps like Lux and Velis Auto Brightness can dynamically manipulate brightness just fine, with no interaction required by the user except for initial setup. So this means that it must be an issue with the GSI itself. But ideally I'd like to find a solution that doesn't involve using apps.