Raspberry Pi 4

Description and Resources

The Raspberry Pi 4 is a versatile single-board computer suitable for a wide range of applications. This guide walks through building Zarhus OS using meta-zarhus, flashing the OS onto an SD card, and accessing the device via UART for debugging.

Additional resources for the Raspberry Pi 4:

• Raspberry Pi Documentation
• Raspberry Pi GPIO Pinout

Zarhus OS Setup

Build Zarhus OS

1. Clone the meta-zarhus repository:

   git clone https://github.com/zarhus/meta-zarhus
   

2. Follow the instructions in the repository's building guide to build Zarhus OS for Raspberry Pi 4.

Once built, you can move onto flashing.

Flash Zarhus OS Image to SD Card

To flash the image to the SD card:

```sh
cd build/tmp/deploy/images/raspberrypi4
sudo bmaptool copy --bmap zarhus-base-image-debug-raspberrypi4.rootfs.wic.bmap zarhus-base-image-debug-raspberrypi4.rootfs.wic.gz /dev/sdc
```

Replace /dev/sdX with your SD card device (e.g. /dev/sdb). Ensure you are writing to the correct device.

UART Console Access

Hardware Setup

To connect via UART for debugging:

1. Use a UART-to-USB adapter and connect it to the Raspberry Pi 4 GPIO pins:

   GPIO Pin	Description
   Pin 6	GND
   Pin 8	UART TXD
   Pin 10	UART RXD

   Refer to the Raspberry Pi GPIO Pinout for the full pinout.

2. Plug the USB end into your host machine.

Software Setup

1. Install a terminal program (e.g., minicom for Linux).

2. Launch minicom on a Linux host to connect to the RPi4:

   minicom -D /dev/ttyUSBX
   

   Also make sure Hardware Flow Control is off (CTRL-A, then Z to open the menu, then O to Configure minicom, then choose Serial port setup, then (if it's enabled) press F to disable Hardware Flow Control).

3. You should now see the Zarhus OS boot console.

From this point, you can login (login root) to monitor and debug the Raspberry Pi 4 running Zarhus OS.