This is a reply to treii28's post from 2023:
To enable i2c on PH4 and PH5 pins, one would have to have to following lines in /boot/armbianEnv.txt files:
Reboot and see the new devices with:
Scan for all the connected i2c devices:
All relevant (and some extra) overlays can be seen with the following command:
To see the configuration one could disassemble the dtb binary file and search it's contents for i2c3-ph
Whenever making changes it would be the best to connect a serial monitor to the physical serial pins (3 separate pins labeled with UART and GND, RX, TX) to see kernel output at boot (115200 baud rate). The kernel log would have a line for loading the dtbo (or maybe an error for missing file:
For easier reference there are included lsmod output, kernel config and dts files from an armbian and the opiz version for "original" debian image (distributed by a sketchy Google drive link, it runs an unnecessary service with weird software repositories enabled by default).
lsmod-armbian lsmod-opiz kernel-armbian.config kernel-opiz.config opz3-armbian.dts opiz3-opiz.dts