Fresh installation after reboot with hdd connected

Hi. I have installed and configured coreelec using and a lightbox connected to one usb of my s905w tvbox. Now i want to have connected an external usb hdd to that usb commection. However if i restart the device with the hdd connected, after booting the coreelec wizard appears and the configuration is gone. If i disconnect the hdd and restart again everything return to my configuration. If i connect the hdd with coreelec launched, it works well as it is detected and i can access to it correctly.

The problem is if i have to restart the device again with the hdd connected, i have to disconnect it first, reboot and connect it again after coreelec launch correctly.

Any help with this?. Thx