Here is the second revision of the board.

I drew the board outline mimic the logo of the KiCon 2023 Asia, and leave the center island of the logo as an SAO connector.

I also find a very cheap 0.85" Memory-in-Pixel Display, so I added the connector on the board.

When I got the sample boards, I found one big error: the switch OFF position will short the battery to ground, and fixed it in the rev2.1

During manufacturing of the samples, I started to learn and write code for the MCU.