Installing U-Boot for LinkStation

For U-Boot port version 2.1.0
16 September 2006

Copyright (c) 2006 Mihai Georgian

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. The full text of the license can be obtained by clicking on the above link.

No liability for the contents of this document can be accepted. The information in this document is provided in good faith but no warranty can be made for its accuracy and the author does not take any responsibility. Use the concepts, examples and information at your own risk. There may be errors and inaccuracies, that could be damaging to your system.

Use of a term in this document should not be regarded as affecting the validity of any trademark or service mark. Naming of particular products or brands should not be seen as endorsements.


Flashing the LinkStation with unauthorised firmare voids your warranty. When installing firmware on an embedded computer things can and, sometimes, do go wrong. The power can go down in the middle of the flash operation or the flash write can fail rendering your LinkStation unusable. Please read this entire page carefully before attempting to install U-Boot.

If you are not prepared to lose your LinkStation, do not attempt to install U-Boot


U-Boot for the LinkStation is distributed as a source patch against u-boot-1.1.4. To compile it you will need either a cross toolchain installed on your PC or native development tools installed on your LinkStation. These instructions assume that you are running Linux on a X86 PC and that you are using a cross toolchain.

To allow testing of U-Boot on your LinkStation without burning it into flash, a kernel module named uloader.o is provided. Uloader allows you to use Linux to load a RAM build of U-Boot and start it. The RAM build of U-Boot is very close to the ROM build. The only differences are the absence of the basic initialisation code (which cannot run from RAM) and the link address. It is strongly recommended that you test U-Boot on your LinkStation using a RAM build before building the ROM version and attempting to burn it into flash. Once you have the RAM build up and running you can use it to install (burn) the ROM version.

Supported Hardware

The LinkStation port of U-Boot described in this document supports the following PowerPC based models:

  1. LinkStation version 1 (model HD-HLAN-1)
  2. KuroBox standard
  3. LinkStation HG (model HD-HGLAN)
  4. KuroBox HG
This version of U-Boot will certainly not work on the the LinkStation version 2 (model HD-HLAN-2) as the LinkStation version 2 is based on a MIPS processor. The MIPS processor is completely different from the PowerPC processor and attempting to flash a LinkStation version 2 with PowerPC firmware it is guaranteed to make it completely unusable.

Get telnet Access

Try to connect to your LinkStation using telnet. If you see the telnet command prompt, read CGI Exploit (PowerPC) original method of Hacking the LinkStation about how to get telnet access.

If the above method doesn't work for you, read Turn your LinkStation into a Kuro Box (PowerPC) for other methods to get telnet access.

The above methods do not work for the LinkStation HG. For this model, the only solution is to load a telnet-enabled version of the firmware. Read the pages about OpenLink and the firmware flasher

You can also try to flash a modified version of the original firmware.

Install the Serial Console

Installing the serial console is not an absolute requirement and it will void your warranty. U-Boot can be installed and controlled without it. However, the serial console will give you the best control over both U-Boot and Linux.

Read Add a Serial port to the PowerPC Linkstation to learn how to install the serial console.

Install netcat (nc)

If you haven't installed the serial console you will need to install netcat (nc). Netcat is a networking utility which reads and writes data across network connections, using the TCP/IP protocol. It comes standard with most Linux distributions. For more information, visit the netcat home page or for the Windows version.

Get the ELDK

If you don't have a cross toolchain installed, download the DENX Embedded Linux Development Kit (ELDK) from, install it and spend some time getting familiar with it.


Create the build directory and set the environment variable UBOOT_BUILD to the path to it

# mkdir <your_build_directory>
# export UBOOT_BUILD=<your_build_directory>

Download the tarball for u-boot-1.1.4 from
Download the LinkStation patch, u-boot-1.1.4-list-2.1.0.diff.gz
Download the uloader module for your LinkStation / KuroBox model.

Untar u-boot-1.1.4 and apply the patch.

# tar xjf u-boot-1.1.4.tar.bz2
# cd u-boot-1.1.4
# gunzip ../u-boot-1.1.4-list-2.01.diff.gz | patch -p1

Untar the uloader archive for your LinkStation / KuroBox model. The archive contains the source code, a binary module compiled for the original LinkStation kernel and a simple bash script to load and start a RAM build of U-Boot.

The binary in uloader-2.4.17.tar.gz has been compiled against 2.4.17_mvl21-sandpoint. Use only on the LinkStation 1 / KuroBox standard.
The binary in uloader-2.4.20.tar.gz has been compiled against 2.4.20_mvl31-ppc_linkstation. Use only on the LinkStation HG / KuroBog HG.

If you have a different kernel version, you may need to recompile the module for your kernel. Compiling the module requires a fully configured kernel source tree. It is recommended to use the same gcc version as the one used to compile the kernel. There is a small but important difference between the two uloader source archives. The difference is the U-Boot load address. If you compile uloader for the LinkStation 1 / KuroBox standard, use the sources in uloader-2.4.17.tar.gz. If you compile for the LinkStation HG / KuroBox HG, use the sources in uloader-2.4.20.tar.gz. In both cases you need to modify the Makefile to match your development environment.

LinkStation 1 / KuroBox standard

# cd ..
# tar xzf uloader-2.4.17.tar.gz
# cd u-boot-1.1.4

LinkStation HG / KuroBox HG

# cd ..
# tar xzf uloader-2.4.20.tar.gz
# cd u-boot-1.1.4

Source your ELDK environment

# . <path_to_your_ELDK>/config_6xx


Edit include/configs/linkstation.h and set the following variables for your environment:

CONFIG_IPADDR_LS  -  the IP address of your LinkStation while running U-Boot (mandatory). The default address is
CONFIG_SERVERIP_LS  -  the IP address of the NFS/TFTP/DHCP/BOOTP server, normally the address of your Linux PC (mandatory). The default address is
CONFIG_NCIP_LS  -  the address of the computer running netcat (nc), normally the address of your Linux PC (optional). If the define is missing, CONFIG_NCIP_LS will be set to the same value as CONFIG_SERVERIP_LS

RAM Build

For LinkStation 1 / KuroBox standard run:

make linkstation_HDLAN_RAM_config
make linkstation_HDLAN_RAM

The name of the resulting binary is u-boot-hd.ram.bin

For LinkStation HG / KuroBox HG run:

make linkstation_HGLAN_RAM_config
make linkstation_HGLAN_RAM

The name of the resulting binary is u-boot-hg.ram.bin

Net Console

The net console is the U-Boot driver which uses the UDP protocol with a default port of 6666 to send the console output to and receive the console input from a remote computer. You need to run netcat on the remote computer to communicate with the U-Boot net console. The communication is bidirectional. Netcat will display on your screen the console output received from U-Boot and will send your keyboard input back to U-Boot.

If U-Boot cannot contact the remote computer, it switches the console to the serial port. To show that it changed the console, U-Boot makes the HDD LED blink with the pattern corresponding to the serial console (see The Reset Button below). The timeout period is 20 sec.

Minimal Console

U-Boot for the LinkStation is designed to allow some control over the boot process even in the absence of a console. For this, it uses the power button (the big button at the front) and the reset button (the small red button at the back).

Before installing U-Boot, when the LinkStation is switched on, the power LED starts blinking, the original boot loader starts executing and, very quickly, it starts booting the kernel from flash. If U-Boot is installed, the power LED will change from blinking quickly to blinking very slowly. The blink pattern is the same as the one used to indicate sleep mode in normal operation. When the power LED starts blinking slowly at boot, U-Boot has taken over and it is counting down the boot delay before booting the kernel. The default boot delay is 10 sec. From the moment when the power LED starts blinking slowly and for the duration of the boot delay, you can control the boot process with the power and reset buttons.

The Power Button

If you push the power button and keep it pressed for more than 1 sec, the boot process will stop and the LinkStation will wait for a command. A stopped boot process is indicated by the power LED being lit solid. The effect is the same a pressing 's' on the console.

A long push of the power button acts as a toggle. If the boot delay count down is in progress, a long push of the power button stops the boot process. If the boot process is stopped (U-Boot is at the command prompt, even if you can't see it), a long push of the power button restarts the boot process resetting the boot delay to its original value. The restart of the boot process is indicated by the power LED blinking slowly.

By default U-Boot supports three pre-configured boot commands:

  1. The first boot command will attempt to load and boot a file named boot/vmlinux.UBoot from the first hard disk partition, /dev/hda1. The file can be in any of the U-Boot bootable formats but uImage is the preferred format. If the file is missing or corrupted, U-Boot will fall back to booting the original kernel from flash.

  2. The second boot command will boot the original kernel from flash.
    Please note that the original kernel for the LinkStation 1 / KuroBox standard has a bug in the function that calibrates the decrementer and it will stop for up to 180 sec during boot. This bug is not an U-Boot bug but a kernel bug which is uncovered by the fact that U-Boot activates the decrementer where the original boot loader does not.
    The original kernel for LinkStation HG / KuroBox HG does not suffer from the above problem.

  3. The third boot command will attempt to boot in emergency mode (EM). It does this by passing the argument root=/dev/ram0 to the kernel.

    LinkStation / LinkStation HG owners should avoid booting in EM mode as the root password for this mode on the LinkStation is unknown.

    The original kernel for the LinkStation / KuroBox standard and for some of the earlier LinkStation HG / KuroBox HG models ignores the root argument. These models will boot normally from the on-board flash when the EM boot command is used. Read the section on EM mode if your LinkStation HG / KuroBox HG has a kernel that doesn't boot in EM mode using this boot command.

You can cycle through the boot commands with the power button.

To see which of the three commands U-Boot is going to execute, press the power button quickly. The HDD LED (the third from the top) will start blinking. The number of times the LED blinks, shows the number of the active boot command. For example, a pattern short on - short off - short on - long off, means that the boot command number 2 is active. U-Boot will repeat the blinking cycle for a total duration of about 5 sec counting from the moment the power button is released.

A short press of the power button while the HDD LED is blinking will advance the boot command to the next one.

Changing the boot command does not change the boot status. If the boot is stopped, it will not be restarted. If the boot is in progress, it will not be stopped but the boot delay will be reset to the original value.

The Reset Button

Two consoles are currently configured, the serial console and the net console. The first console is the serial console and the second console is the net console (nc). The net console is the default console.

The reset button can be used, similarly to the power button, to switch consoles. A press on the reset button (here, it doesn't matter how long you keep the button pressed) displays the currently active console using the HDD LED. Repeatedly pressing the reset button while the HDD LED is blinking will toggle between the two consoles. The blinking pattern is different from the one showing the boot command. The pattern which shows that the second (net) console is active is short off - short on - short off - long on. U-Boot will repeat the blinking cycle for a total duration of about 5 sec counting from the moment the reset button is released.

Load and Test

Mount the LinkStation SMB public share and copy the following files to it:

For LinkStation 1 / KuroBox standard

# mount -t smbfs -o password="" //<your_linkstation_name_or_ip>/share/mnt
# cp u-boot-hd.ram.bin /mnt
# cp ../uloader-2.4.17/uloader.o /mnt
# cp ../uloader-2.4.17/ /mnt
# umount /mmt

For LinkStation HG / KuroBox HG

# mount -t smbfs -o password="" //<your_linkstation_name_or_ip>/share/mnt
# cp u-boot-hg.ram.bin /mnt
# cp ../uloader-2.4.20/uloader.o /mnt
# cp ../uloader-2.4.20/ /mnt
# umount /mmt

If you installed the serial port, open another window and use minicom to connect to your LinkStation serial console. The serial port settings are 57600,N,8, the same as the settings used by the original Linux kernel.

Start netcat to communicate with the U-Boot net console. Open another window and run board/linkstation/ is a simple script which invokes netcat with the correct options. To quit nc, press ^T (control-T).

# cd $UBOOT_BUILD/u-boot-1.1.4
# board/linkstation/ <ip_of_your_linkstation>

Where <ip_of_your_linkstation> is CONFIG_IPADDR_LS (see Configure U-Boot above). When you run nothing will be written to the screen. This is normal as Linux is not using the net console.

From your original window, use telnet to connect to the LinkStation and launch U-Boot. Replace lshg in the example below with the name / IP address of your LinkStation. Replace myroot with the login you created when you gained telnet access. For LinkStation 1 / KuroBox standard, use instead of Type the commands shown in bold.

# telnet lshg
Connected to lshg.
Escape character is '^]'.


HD-HGLAN6C5 login: myroot
Linux (none) 2.4.20_mvl31-ppc_linkstation #3 Thu May 19 13:34:18 JST 2005 ppc unknown
root@HD-HGLAN6C5:~# cd /mnt/share
root@HD-HGLAN6C5:/mnt/share# ./
root@HD-HGLAN6C5:/mnt/share# exit
Connection closed by foreign host.

If you have a serial console you should see the initial U-Boot startup messages. Even if the default console is the net console, U-Boot still sends the console output to the serial port until it initialises the network controller.

U-Boot 1.1.4 LiSt 2.1.0 (Sep 12 2006 - 23:09:44) LinkStation HG / KuroBox HG

CPU: MPC8245 Revision 1.4 at 262.144 MHz: 16 kB I-Cache 16 kB D-Cache
DRAM: 128 MB
*** Warning - bad CRC, using default environment

        00  0b  10ec  8169  0200  ff
        00  0c  1283  8212  0180  ff
        00  0e  1033  0035  0c03  ff
        00  0e  1033  0035  0c03  ff
        00  0e  1033  00e0  0c03  ff
Net:   RTL8169#0

Watch the net console window. After a few seconds, time needed by U-Boot to initialise the network controller and the IDE controller you should see the U-Boot messages.

U-Boot 1.1.4 LiSt 2.1.0 (Sep 12 2006 - 23:09:44) LinkStation HG / KuroBox HG
IDE:    Bus 0: OK
  Device 0: Model: Maxtor 7Y250P0 Firm: YAR41BW0 Ser#: Y62W8PDE
            Type: Hard Disk
            Supports 48-bit addressing
            Capacity: 239372.4 MB = 233.7 GB (490234752 x 512)
Boot in 10 seconds ('s' to stop)...

Press 's' on your keyboard to stop the boot process.

If you want to use the serial console, watch the power LED of your LinkStation. When it starts blinking very slowly, use the power button to stop the boot process. Wait for the power LED to go dim and press and hold the power button until the LED lights up brightly indicating that the boot process has stopped. Now press the reset button twice and you should see the U-Boot command prompt (=>) in your minicom window. You can now control U-Boot from the minicom window.

Using / leads to the above results on devices with the original software. On some LinkStations with modified software, reboot has been modified to send a reboot command to the AVR. This is indicated by the fast blinking of the power LED immediately after running / Once the AVR receives a reboot command, the reboot process cannot be stopped. The AVR will reboot the LinkStation 5 min after receiving the reboot command.

If you find yourself in the above situation you can still test U-Boot by booting your LinkStation with the AVR disabled. Press and hold the reset button and then press the power button. All LEDs will start flashing but your LinkStation will boot normally. Now you can use the procedure described above with one caveat: the AVR being disabled, pressing the buttons will have no effect so you will not be able to test the behaviour of the minimal console. When you finish testing, press and hold the power button and the LinkStation will switch off.

Once you get the U-Boot command prompt, start testing it. Read the U-Boot documentation and try each command you are interested in.

Keep in mind that U-Boot interprets all input number as hex numbers. If, for example, you type 256, U-Boot will interpret it as 598 decimal.

When you are testing memory write commands, do not attempt to write to the first MB of memory (0x00000000 to 0x00100000) as you will be overwriting the exception vectors and U-Boot will crash.

An important command is flinfo which displays information about the flash chip. If the information displayed is correct for your flash, test the flash erase and flash write commands. To do this, you will need to find an empty sector, one for which each byte is 0xFF. Hint: check the last flash sector first, chances are that it's empty. When you are testing commands that write to the flash, always remember that you can write a single byte but you can only erase whole sectors.

Be very careful not to write to the flash memory range 0xFFC00000 to 0xFFF7FFFF. This area contains the Linux kernel, the initial RAM disk used for EM mode, the bootloader and the configuration sector (which holds the "OKOK" or "NGNG" pattern). The range 0xFFF80000 to 0xFFFFFFFF is the user area and, in most cases, is empty. Always check using the U-Boot command md (memory display) if the flash area you intend to use is empty (all bytes are 0xFF). For more information about the flash organisation, read PPCFlashROM for the LinkStation 1 / KuroBox standard or HGFlashROM for the LinkStation HG / KuroBox HG.

ROM Build

Once you are happy with the RAM build, you are ready for the ROM build.

For LinkStation 1 / KuroBox standard run:

make linkstation_HDLAN_config
make linkstation_HDLAN

The name of the resulting binary is u-boot-hd.flash.bin

For LinkStation HG / KuroBox HG run:

make linkstation_HGLAN_config
make linkstation_HGLAN

The name of the resulting binary is u-boot-hg.flash.bin


Do not attempt to flash from U-Boot if the power LED is blinking. Your LinkStation is likely to reboot and you will end up with a "brick"

Test the flash commands thoroughly before deciding to burn U-Boot into flash. Write at least 128 kB to the flash to test potential timeout problems

The flash routines in this version of U-Boot for the LinkStation should be able to identify and handle any CFI flash which uses the AMD standard command set. However, they were tested only on a LinkStation with a Fujitsu MBM29PL32TM flash chip and on a LinkStation HG with a ST Micro M29DW324DB flash chip.

Be very careful not to flash your hardware with the wrong U-Boot build. Flashing any RAM build or flashing a ROM build for the LinkStation 1 / KuroBox standard into the LinkStation HG / KuroBox HG or viceversa will "brick" your device. This is especially true if you are flashing from Linux as U-Boot has safety checks to avoid flashing the wrong build.

Flashing U-Boot from U-Boot

The RAM build of U-Boot can be used to load and flash the ROM build. This is the preferred method.

Boot your LinkStation normally. Open a telnet session and create a directory to hold the U-Boot flash image.

root@linkstation:~# cd /mnt/share
root@linkstation:/mnt/share# mkdir u-boot

Copy the U-Boot flash image to your LinkStation SMB share in the directory u-boot.

Load the RAM build of U-Boot and at the U-Boot command prompt type:

=> run upgrade

U-Boot will attempt to load the ROM build from the directory share/u-boot/ on the third partition of the hard drive. If the load is successful, it will do the following:

  1. unprotect the bootloader area;
  2. erase the bootloader area;
  3. copy the loaded file to the bootloader area;
  4. verify the copy;

Here is the output of run upgrade

=> run upgrade
Loading 0:3:share/u-boot/u-boot-hg.flash.bin

174668 bytes read
Un-Protected 3 sectors

Flash erase: first = 55 @ 0xfff00000
             last  = 57 @ 0xfff20000
Flash erase: Done
Erased 3 sectors
Copy to Flash... done
Total of 174668 bytes were the same

When the above sequence finishes, U-Boot returns to the command prompt (=>).

Depending on your flash chip, the flash operation can take a long time. Wait patiently and do not try to power down or otherwise interrupt the flash or you will end up with a "brick".


=> reset

The power LED should start blinking slowly and, if you have a serial console, you should see the U-Boot startup messages. Your LinkStation is now running U-Boot.

Flashing U-Boot from Linux

Connect to your LinkStation using either the serial port or telnet.

For LinkStation 1 / KuroBox standard run:

# cd /mnt/share/u-boot
# dd if=u-boot-hd.flash.bin of=/dev/fl2 bs=1k
# cmp u-boot.bin /dev/fl2

For LinkStation HG / KuroBox HG run:

# cd /mnt/share/u-boot
# dd if=u-boot-hg.flash.bin of=/dev/mtd1 bs=1k
# cmp u-boot.bin /dev/mtd1

The above commands for LinkStation HG / KuroBox HG will work on devices with the original kernel version 2.4.20 but might to work on earlier devices using kernel version 2.4.17. Please check which device corresponds to the bootloader partition on your hardware.

If the Flash Fails

If the flash was not written correctly but U-Boot returns at the command prompt, try to re-run run upgrade.

If the same happens when you attempt to install U-Boot from Linux, try to dd again.

If your flash fails completely, for example due to a power failure, all is not completely lost. You can still use a JTAG cable to re-flash your Linkstation. Unfortunately, this is a relatively complicated and expensive solution as it involves acquiring or building the JTAG cable and soldering the header for it on the LinkStation motherboard. For more information on how to use a JTAG cable with the LinkStation you can visit and

EM Mode

Warning for the LinkStation / LinkStation HG users

Do not attempt to boot into EM mode using the method described here. The password for the EM mode is unknown for all LinkStation models.

Once you have U-Boot installed in the on-board flash, you can boot in EM mode even if the third boot command described above doesn't work.

Stop the boot countdown by pressing 's' in your net console window and, at the U-Boot command prompt, run:

=> run writeng
=> run flboot

The above commands write "NGNG" to 0xFFF70000 and boot from the on-board flash. To revert to normal boot by writing "OKOK" to 0xFFF70000, run:

=> run writeok
=> boot

Advanced configuration

The initial U-Boot configuration can be changed by editing the file include/configs/linkstation.h.

In all the examples below, please note the backslash-zero (\0) at the end of the strings and the space-backslash ( \) at the end of each lines and do not change them.

Change the name of the default boot file

Search for the lines containing:

"hdpart=0:1\0" \
"hdfile=boot/vmlinux.UBoot\0" \

and change them to the values you want. Partition 0:1 means disk 0, partition 1. Obviously, you can only change the partition number as there is only one disk. The name of the file must be given relative to the root of the partition.

Change the default console to the serial console

Search for the lines containing:

"stdin=nc\0" \
"stdout=nc\0" \
"stderr=nc\0" \

and change them to:

"stdin=serial\0" \
"stdout=serial\0" \
"stderr=serial\0" \

Change the default boot command to boot from flash

Search for the lines containing:

"bootcmd1=run hdboot;run flboot\0" \
"bootcmd2=run flboot\0" \

and change them to:

"bootcmd1=run flboot\0" \
"bootcmd2=run hdboot;run flboot\0" \