Why?

You might not have reach that point yet but bluez has been deprecating hciconfig and other tools. In bluez 5.44, it’s not there anymore.

What is the problem?

All hciconfig udev rules to activate bluetooth at startup won’t work anymore. Most forum posts solving bluetooth issues are now outdated. Once I updated to bluez 5.44, my service leveraging hciconfig to activate bluetooth at startup didn’t work anymore!

What is the solution?

It’s now actually documented in the archwiki

Alternatively and instead of the custom service and udev rule, you can simply use the new AutoEnable feature introduced in BlueZ 5.35 by uncommenting  [Policy] and AutoEnable=true lines in /etc/bluetooth/main.conf.

Just uncomment and go, you don’t need the service to activate bluetooth anymore, enjoy!