Debian Bullseye's installer is on a USB stick and I used it to boot into Rescue Mode. If it's of any relevance, the partition table type is GPT, with UEFI+Secure Boot enabled.
After booting into Rescue Mode and filling out the required details onscreen, I chose /dev/perfect-vg/root as the device to use as root file system. If you may recall, the volume group perfect-vg is LUKS-encrypted. When asked if I wanted to mount the separate /boot/efi partition, I entered No. Next, I entered Executive a shell in /dev/perfect-vg/root I typed the command nano /etc/apt/sources.list and commented out all the lines therein. I added the the following line: deb [trusted=yes] file:/media/myusb bullseye main I saved the sources.list file. I created a directory called /media/myusb and issued the following command to mount the USB stick to it: mount /dev/sdb1 /media/myusb The error message is: mount: /media/myusb: /dev/sdb1 already mounted or mount point busy Below are the results of cat /etc/fstab <file system> <mount point> <type> <options> <dump> <pass> /dev/mapper/perfect--vg-root / ext4 errors-remount-ro 0 1 /boot/efi was on /dev/sda1 during installation UUID=A30E-2C33 /boot/efi vfat umask=0077 0 1 /dev/mapper/perfect--vg-swap none swap sw 0 0 /dev/sr0 /media/cdrom0 udf, iso9660 user, noauto 0 0 /media/myusb I appreciate your help in this matter.
