Kind of Confused.
You want to build your own kernel?
-If you want to do that I recommend a tool such as buildroot or openembedded. It makes kernel building for embedded devices as well as a rootfs easy.
Where are you getting stuck with porting your kernel
writing it to nand?
kernel boots but no messages?
http://linuxsoftware.co.nz/wiki/Mini2440
If you want to transplant the kernel from one board to another that may be tricky?
-mini2440 use u-boot (a custom u-boot fork- the one that ships with buildroot will not work due to the stepping stone issue) you could possible get into the u-boot
run mtdparts find the partition on the board and it's size read the partition into memory and write it to a FAT32 usb drive. That or Jtag the board and dump the whole nand flash
What are you trying to do exactly