If your system uses systemd, you could write a oneshot service that executes the command once, at system boot.
First, create a file
/opt/scripts/configure-bluetooth.sh and put your commands in:
rfkill unblock bluetooth
hciconfig hci0 up
And make the file executable:
chmod +x /opt/scripts/configure-bluetooth.sh
The create a new service unit:
/etc/systemd/system/configure-bluetooth.service That contains:
You should now run
systemctl daemon-reload so that systemd detects the new service. To test it, run
systemctl start configure-bluetooth.service.
Once you are sure that it works, you can enable it on boot with:
systemctl enable configure-bluetooth.service