Quote from Computer Audio:
"I don't think Z1ES boots from internal hard drive, it boots from some SSD inside.
Because after I install the new drive(indeed new drive, blank, NTFS formatted), booted properly but Z1ES no longer sees it, and I can't format it. I have to do factory reset from the settings, and after that, it formats the disk, and guess what? All sample music is copied to the new drive! So there is a separate storage on board with OS and sample data. The original 1TB drive is only for music and database."