Restoring Stock Firmware via TFTP

Notes before you begin
Most if not all of Buffalo devices allow for re-installing the firmware by loading the boot files from the network via TFTP.

For Intel-based devices the process involves creating and then booting from a usb recovery disk. Information about creating a recovery disk can be found here: Create Recovery Disk for Intel-based Terastation

Some devices have a built in method for installing the firmware from their on-board NAND flash which is typically easier that following this method. Check the wiki page for the device and/or the user's manual to see if that option is available to you.

For best results start with completely blank drives. It is usually sufficient to prepare one drive as described below and leave the others completely blank.

Most multi-bay devices won't install the firmware successfully without a certain number of drives present. I haven't investigated every combination of model and number of disks, but generally:
 * 2-bay usually require a drive in both bays
 * 4-bay models vary (some share firmware with 2-bay models and will accept 2, others won't)
 * 6-bay and 8-bay models usually need a minimum of 4 drives.

Note: Some 2-bay models may incorrectly set their number of drives as 4 and refuse to install with only 2 drives (TS1200, TS-WVHL and possibly others). To correct this or if you just want to set up the device with less than the maximum number of drives you can run the following command via ACP Commander when the device is in EM Mode before you start the install: java -jar acp_commander.jar -t -c "echo MAX_DISK_NUM=2 >> /etc/nas_feature" This will only affect the current EM Mode session and has no permanent affects on the device.

Once the firmware is installed most devices are perfectly happy running with just 1 disk if that's what you want.

There is a minimum disk size which is different for different models. This isn't usually a problem since the minimum is usually much smaller than one would typically use with a NAS. For example I found that most older devices will happily install their firmware on 32GB SSD but not a 16GB SSD, for many newer devices I found even that didn't work for testing.

Extract Boot Files from Stock Firmware

It basically consists of booting the device into EM mode using the files extracted from the firmware and the performing the install using the firmware installer in Debug mode:

Enable Debug mode