Do not try Ubuntu 16+ or standard Fedora 30+ – the XO-1’s 256 MB RAM will cause immediate crashes.
Use a tool like Rufus (Windows) or dd (Linux/Mac) to write the downloaded .img file to your USB drive.
The XO-1 often refuses to flash a new OS if the battery is dead or missing. If you are running solely on AC power, you may need to bypass the battery check in the Open Firmware (OFW) by typing fs-update commands manually. Slow Performance