Power PMAC memory and Linux question

What goes in the 64 MB of NOR flash as opposed to the 512 MB of NAND flash? Do you provide copies of the initial contents of the NOR and NAND flash? Can we reflash them in the field? How would we reflash them? Is there a chance of "bricking" the board when reflashing it? Where is the Linux kernel or the root filesystem stored? How would I arrange for my own servers to be started when the system boots? I normally start my servers with an /etc/init.d style script.[hr] The NOR flash consist of a bootloader, kernel and device tree. The initial contents can be flashed using the flashcp command available in linux. Our IDE provides an interface to do this so no command line usage is necessary from the user. The bootloader should rarely need to be flashed (if ever). If the bootloader is flashed incorrectly the board will need to be returned to the factory to be reprogrammed using a special JTAG programmer. The kernel or device tree get screwed up they can be fixed in the field as the bootloader allows reprogramming the NOR flash using tftp or a usb stick with commands over the RS232 port. See www.denx.de and its manual for the commands. The 512MB NAND flash has been increased to 1G and contains a debian 5.0 filesystem. Since we use a standard debian 5.0 file systems you can start your own stuff using /etc/init.d. However, for reliability our filesystem is mounted readonly. /etc and /var are composed using the AUFS filesystem. The /etc contents are actually be stored in /.readonly/etc. Below is how we mount etc