Is it possible to set static IP on SD card with Hass.io instead of USB stick?

I’ve configured USB stick following this tutorial since my router doesn’t have an option for DHCP reservation.

It works but just for simplicity, I’m curious if it’s possible to achieve the same outcome using just SD card with Hass.io install in my Pi 3? I guess not but I’d rather ask.

Yes you can. Create a CONFIG folder in boot partition.

Doc here:

Doesn’t work. It even made my Hassio not bootup.

What brand router? Never seen one that won’t let you reserve an IP address for a device

Provided from my ISP with their firmware. But I’m planning to change it in the near future.

Did you create the CONFIG folder (in uppercase) at the root of the Disk partition? and put files in it?
From the HassOS code, this folder should be mounted in /mnt/config/CONFIG at boot