This is an additional project to 
https://github.com/TripleHelixConsulting/meta-thc-v1
The main project contains a full detailed PDF. Here are the most important points from its README:
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This is a complete EXAMPLE PROJECT WITH GUIDE for creating a YOCTO build for RASPBERRY PI (RPI).

The main target is RPI4, but with minimal edits it shall support any Yocto-supported RPI with HDMI.

The project is up-to-date with the Detailed Manual pdf document, titled:
"Manual for Custom Yocto-based minimal Linux Image for Raspberry Pi.pdf"

The document contains many sections, some of which are:

2. Yocto in 5 minutes from a technical perspective___________________________________________________4
3. What do you need on Manjaro to run a Yocto build________________________________________________7
4. The RPI 4B Platform and the Display___________________________________________________________7
5. Yocto and Raspberry PI_____________________________________________________________________8
7. Yocto versions and information, how to know what kernel version do we build from Poky__________________9
8. The BitBake build steps_____________________________________________________________________10
9. Fetching the project and building it yourself - super easy, with only a few commands_____________________12
10. Our project structure and bitbake basics_______________________________________________________14

11. Starting the board________________________________________________________________________21
Using halt and reboot_____________________________________________________________________22
Connecting via SSH______________________________________________________________________22

12. Networking and starting the WiFi____________________________________________________________23
13. The SW provided by our image______________________________________________________________23
BusyBox, Shell, Init system, Libraries, X11, Avahi, Dropbear SSH, wpa_supplicant,...
Looking for other modules, present or not.__________________________________________________26
Logs, Kernel, Editor, Clock

16. Processor, CPU Speed, and HW specification_______________________________________________26
17. Adding a module______________________________________________________________________27
14. IMGUI DEMO___________________________________________________________________________27
15. Changing for different HW__________________________________________________________________28

16. Important Yocto Links_____________________________________________________________________28

17. License, development, and contribution_______________________________________________________29
18. Change Requests, Bugs, Contributions, New Features___________________________________________30
19. Projects and work orders, partnerships________________________________________________________30
20. Copyright notice

If you are interested in this project, we will be glad to know and potentially collaborate. In this case, please contact <office at triplehelix-consulting dot com>.
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