From NAS-Central Buffalo - The Linkstation Wiki
Currently, the Kuroboxes all use a Fujitsu 29PL32TM-90PFTN 4MB Flash ROM chip. The Flash ROM houses vital information such as the Linux kernel for standard operation and emergency mode, as well as the code for booting into the kernel. The contents are layed out in different ways depending on which Kernel you are using. Flash ROM chip data can be updated, deleted, or reprogrammed through the Linux console or via the optional JTAG port.
Reprogramming the Flash ROM
Please be very careful when reprogramming your Flash ROM. Overwriting or erasing your Flash ROM can turn your Kurobox into a brick.
The interest in reprogramming the Flash comes mostly from the desire to run a custom kernel than the stock one that is packaged with the Kurobox. This is possible by overwriting the original bootcode with U-Boot.
Flash ROM Layouts
Stock 2.4.x Kernel
|/dev/fl3||0xFFF70000||0x010000||64K||HDD status (OKOKOK)|
Patched 2.6.x Kernel v1
Patched 2.6.x Kernel v2
Additional Flash Chip?
There has been some discussion going on at the Kurobox forums, regarding the possibility of adding an additional Flash chip.