From NAS-Central Buffalo - The Linkstation Wiki
This article Based on work done by frontalot at Linkstationwiki.org
There is a possibility that you could brick your NAS with these instructions. Please make sure that you read the entire page carefully. this is ONLY applicable to the PowerPC HD-HLAN (LS1). All subsequent models of the LinkStation use the mtd block mapped flash device because the kernels have moved beyond 2.4.17.
This is really just background information and only advanced users should be poking around in the flash as this could result in being the proud owner of a toaster. Do not manually flash your firmware unless you are absolutely sure about what you're doing! You should read the flash ROM analysis at: LS Hardware and Software information before proceeding. This is for changing the EM mode load only, and this shouldn't be used for changing the firmware. The LinkStation firmware flasher would be the way to go usually.
1. You will need the firmimg.bin of your desired firmware. Copy firmimg.bin to your LinkStation.
2. Open up an SSH or telnet session to the LinkStation. Copy firmimg.bin to the /dev/fl1 flash bank:
cat firmimg.bin > /dev/fl1
3. The LinkStation LEDs will begin flashing red; this is normal! The flash process may take several minutes. Absolutely do not turn off the LinkStation, terminate the SSH/telnet session, or in any other way interrupt the flash process. The LEDs will return to normal when the flash process is complete.