Now you can start testing Android 12 from your Raspberry Pi 4, 400 or CM. As you hear, even if your mobile phone does not yet support the latest release of Google's operating system, now you can test it and try all the new features thanks to XDA KonstaT (KonstaKANG) and the unofficial compilation of LineageOS 19.0, which is based precisely on version 12.
And the truth is that it is not only useful for testing, but it can also serve as your usual operating system, since works quite well, like other operating systems designed for the Raspberry Pi. You will only have to download the image of the operating system based on Android 12 and transfer it to a microSD memory card, as you would like any other OS.
When you start this Android operating system you will not have an initial configuration for a Google account or anything like that, you simply start the system from the SD and enter the desktop session. You will see that you have two workspaces available by default, although you can easily customize it to change the widgets, wallpaper, etc.
You can connect to the internet via DualBand WiFi as with other OS, and also have Bluetooth support. So you can download new apps, surf the net with a browser, etc. On the other hand, the interface is fluid and easy to use, allowing you to slide the screen as you would with a mobile phone, but with the click of the mouse to scroll to the available menus and apps (Calculator, File Manager, Calendar, Contacts, Clock, Voice recorder, Photo gallery, Music, Web browser, Camera, Settings…).
You'll be able to enjoy many Android 12 features on your Pi, including dark mode, support for multi-touch displays, including USB displays, or Waveshare SPI, etc. However, there are still some restrictions, such as the playback of YouTube videos, which cannot yet be done in HD or FullHD resolutions. The developer is working on it, to add more codecs.
You can also connect to the ports of your Raspberry Pi a multitude of peripherals, such as external hard drives or pendrivers, mouse and keyboard USB, etc. Includes support for GPIO, SPI, USB-C (ADB, MTP, PTP), sensors (accelerometers, gyroscope, humidity, magnetometer, pressure, temperature), GPS by using an external USB module such as U-BLox 7, Ethernet, HDMI and HDMI-CEC displays, and I2C IR remote controls, with modules.