I use ddrescue for failingt hard drives. I have an HP AIO 20 come in the other day. It would not boot up. Said it couldn't find the hard drive. I open up the AIO and hook the hard drive to my bench machine. Booted up parted magic. I run the lsblk cmmand to see what device to copy and it wasnt listed. Instead of /dev/sdXX it said loop254 and loop XXX(can not remember). Restarted a couple times and even tried another bench PC. Does this mean it bad hard drive or is it something else. Also doesnt show up in gsmartcontrol.