Does it boot?

Can you post SDK so I can see what software they have built? For example gstreamer driver?

optional use case...
4) POE with no screen

Maybe you can put pins in the right places to use off-the-shelf POE module.

Something similar to this
https://item.taobao.com/item.htm?spm=a230r.1.14.64.7cb06c02UjTec6&id=16848013654&ns=1&abbucket=15#detail

Another style
https://www.aliexpress.com/item/33012224035.html

Random 8080 pinouts can be handled by having the FPC on the V831 board support the LCD you are going to sell. Any other pin out will need to make a small PCB with two FPC connectors and remap the cables.

Those two I2S lanes on V833 likely for four mics. TDM I2S mic more expensive than non-TDM ones so with four lanes you can use the cheaper versions. I don't know any other reason for two I2S lanes other than to support 4 mics.

Two mics fine on V831 board.

Those pins also useful for attaching smart mic chips.
https://www.aisonic.com/

Consider three use cases:

1. LCD attached to PCB with camera
2. standalone camera using wifi, no display
3. USB cable from board back to host PC.

You could make assembly like a sports camera, sensor pointing forward with display on the back.
https://www.youtube.com/watch?v=vFIzRwujxyw

V831 does not support MIPI display

No direct FPC connectors for camera and LCD? Or even mount sensor to PCB. Then use microJST for Ethernet and GPIO?.

Like a normal security camera module?
https://item.taobao.com/item.htm?spm=a230r.1.14.112.60d45537OwB9xb&id=544437366567&ns=1&abbucket=15#detail

Should be cheaper to make using security module type design. You only need one PCB.

I have been looking at V831 more and I am convinced a V831 board will beat a K210 one.

1. H.264 encode. This is a major thing missing from K210, there is no way to record the video the AI unit sees so that you can use it later for training.
2. Easier to program, it runs Linux easily. K210 Linux hard.
3. More memory, K210 memory quite constrained
4. SOC is slightly cheaper.
5. ISP for video noise reduction and resizing
6. Common ARM CPU with compilers available everywhere
7. OTG USB

Minuses

1. Much better audio support on K210. Allwinner could have done more on V831.
2. No FFT unit

I'd copy the K210 Maix product offerings, they have a good array of choices.

Another mistake Allwinner made is no h.264 decode. That prevents you from making a sports cam type device with this chip. There is no way to display the saved h.264 video.

I am trying to get this SDK working on a cheap Allwinner SOC.
https://github.com/alexa/alexa-smart-screen-sdk

That is the SDK to build an Echo Show...
https://www.tomsguide.com/us/amazon-echo-show-5,review-6594.html
The real Echo Show contains a Mediatek MT8163 and 512MB DRAM.

Currently we are targeting H6, 512MB X3 would work too.

That SDK depends on having a browser (webkit, chrome, firefox will do) accessible. Current browsers need a GPU so this browser dependency forces a CPU with a GPU.

Without 512MB it can't run a browser. Being able to run browser would make this chip much more useful.

Have you seen a price for the 512MB version of X3?