I suddenly have a Hard Fault 0x00018fc2 when powercycling and booting NG via USB Power / USB Data Connection. If the bootloader jumper is connected i can use the USB Connection to upload the bootloader . but after uploading NG  again and rebooting , it wont boot back up after power cycling the USB Connection. The App will boot properly with external power and detached USB cabel.   this suddenly occured i use a self powered usb hub . i tried disconnecting all attachm