@Lucas: I think not putting kernel into a regular partition has several benefits:
1.) the boot loader is easier to configure - it just needs to know a fixed offset / flash memory address
2.) the kernel cannot be easily corrupted as would be the case with file system
3.) embedded devices cannot boot easily from - say - a USB stick or Linux Live CD. There must be an easy way to install kernel, filesystem etc. Often - as with Android - uboot bootloader provides a way to put the device into some boot loader mode such that the kernel can be flashed via USB.
More info at
http://www.denx.de/wiki/U-Boot
Anyways - if you want to boot the kernel from a boot partition, you may need a different boot loader. You may have a look at the Kobo Debian Linux image - maybe it does have something like Grub or Syslinux:
https://www.mobileread.com/forums/sho...d.php?t=222123