Debian Installer's Rescue Mode

I just used DI's Rescue Mode to fix a(n) FDE installation almost effortlessly. Basically, the Rescue Mode mounts /, /boot, and /boot/esp (if applicable), and performs chroot for the user. A terminal with root privilege is opened for the user, allowing the user to fix the existing installation.

For example, I started my workstation this morning and see the Grub Rescue information. I simply booted into Debian Installer (binary installation media), chroot'ed and run # update-grub. There was an error because the command tried to add the boot entry for the USB device (the Debian Installer) but unsuccessful. The entire process took only 2~3 minutes.