During standard Debian install i decided to go with  implementing additional security factor which is /boot on separate USB key. In Debian guide I've found it is only put this way.http://madduck.net/docs/cryptdisk/if you don't like the unencrypted /boot partition, you could boot the system off a USB key, which you can keep separate from the system except for when booting and upgrading the kernel. All you need to do for that is install the bootloader and kernel onto the device and configure it to use the proper encryption volume on the harddisk as root filesystem.I know how to install GRUB onto USB stick grub-install --root-directory=/mnt /dev/sdbbut I don't know hot to copy kernel image from my current installation to USB stick. Everything is done here from live environment. On clean install, I setup partitions manually and then proceed with installation, after my /root and  /home are ready to use and /boot is already specified on USB Key I choose to Continue Testing my live environment from which I install GRUB onto /boot partition but how do i put initial ramdisk there? Because this is mandatory for system to boot. Also does this approach doesn't require my to edit my /etc/fstab or /etc/crypttab?
Separate /boot partition on USB
debian;boot loader