USB flash drive/scripts/casper-premount/2-iso_scan: line46can 'topen/dev/sr0: NoMediumfound solution

USB flash drive system installation/scripts/casper-premount/2-iso_scan: line46can & amp; #39; topen/dev/sr0: NoMediumfound solution when installing backbox for USB flash drive (based on ubuntu, encountered this problem/scripts/casper-premount/2-iso_scan...
USB flash drive/scripts/casper-premount/2-iso_scan: line 46 can't open/dev/sr0: No Medium found, encountered this problem/scripts/casper-premount/2-iso_scan: line 46 can't open/dev/sr0: No Medium found, after checking the materials for half a day and making continuous attempts, I found a solution. The error message is that the optical drive cannot be found, indicating that the menu. lst may be wrong, so you can modify the drive and the system starts successfully. Menu. lst is www.2cto.com [html] title-> BackBox kernel/casper/vmlinuz file =/preseed/backbox. seed boot = casper quiet splash initrd/casper/initrd.gz boot PS: The files casper and preseed are in the root directory of the USB flash drive.