[Lenovo P11] Slimerang:
Yesterday, I decided to give the Android 12 GSI a try. The package comes w/ system.img and vbmeta.img. I took my 12L tablet, put it in fastboot via recovery, and since it was already flashed w/ boot, dtbo, and vendor, I just skipped to vbmeta and system. I do all this under my Linux system, so:

$ fastboot --disable-verity --disable-verification flash vbmeta gsi/vbmeta.img
Rewriting vbmeta struct at offset: 0
Sending 'vbmeta_a' (4 KB) OKAY [ 0.002s]
Writing 'vbmeta_a' OKAY [ 0.005s]
Finished. Total time: 0.022s
$ fastboot --disable-verity --disable-verification flash vbmeta gsi/vbmeta.img
$ fastboot erase system # optional
Erasing 'system_a' OKAY [ 0.091s]
Finished. Total time: 0.098s
$ fastboot flash system gsi/system.img
Invalid sparse file format at header magic
Resizing 'system_a' OKAY [ 0.005s]
Sending sparse 'system_a' 1/11 (262108 KB) OKAY [ 10.257s]
Writing 'system_a' OKAY [ 1.534s]
# deleted for brevity
Sending sparse 'system_a' 11/11 (42372 KB) OKAY [ 1.696s]
Writing 'system_a' OKAY [ 0.236s]
Finished. Total time: 104.110s
$ fastboot -w reboot

And that booted up fine. No Magicsk stuff. What does that get me? Root? Didn't seem to be required.

Anyway, immediately I noticed that the fingerprint scanner did not work which was depressing. I messed around a bit, but was not very happy. So I decided to try the Pixel experience ROM like @famaTV has mentioned. I downloaded PixelExperience_arm64-ab-12.0-20211226-UNOFFICIAL.img, got back into fastboot, and then flashed it:

$ fastboot erase system # optional
Erasing 'system_a' OKAY [ 0.076s]
Finished. Total time: 0.083s
$ fastboot flash system PixelExperience_arm64-ab-12.0-20211226-UNOFFICIAL.img
Invalid sparse file format at header magic
Resizing 'system_a' OKAY [ 0.005s]
Sending sparse 'system_a' 1/14 (262108 KB) OKAY [ 10.054s]
Writing 'system_a' OKAY [ 1.518s]
# deleted for brevity
Sending sparse 'system_a' 14/14 (54348 KB) OKAY [ 1.970s]
Writing 'system_a' OKAY [ 0.098s]
Finished. Total time: 134.571s
$ fastboot -w reboot

It booted up fine. Got Pixel boot animation and then it started asking me to setup my Pixel device and such. Now it was kind of janky when it booted that first time. It was missing touches and such. I could barely get the fingerprint reader to take one complete registration. I logged into Google account and was able to update apps via Play Store normal updates. The whole Pixel setup stuff was not working correctly on that first boot. It kept spinning on setting up. After a bit of that, I restarted it and everything went much better. It finally asked me to restore the tablet from a backup which worked great. I also added a 1 TB microSD card and it worked correctly. At this point everything that I have thought of to check works and works well. The device does think it is a phone more than it should. Like the Google Messages app that comes on the device is expecting to be on a phone. But once I device paired thru Chrome it let me download a different Google Messages app that works like it is supposed to where it uses my real cell to do all the texting.

This experience is vastly superior to original CN ROM. I'm not even sure if I'd ever need to put a real Lenovo ROM on here. At that point I can not worry about the region code. I've attached a few screen shots from the Pixel Xp system FYI.

Oh, Netflix is only showing L3 even though DRM Info shows L1. Not sure how to get that fixed or even if it is fixable. That may be a deal breaker for some.

Hopefully 12L will get to this level of performance and I can get this thing to not think it is a phone. I'm not sure if I remember checking Netflix DRM level...