Building and using Openwince's JTAG Tools

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Revision as of 19:00, 30 August 2006 by Dtaylor (Talk)

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This page is under construction and may contain mistakes or have missing information. Use of this information is at your own risk and may further damage your hardware. YOU HAVE BEEN WARNED


There is a possibility that you could brick your NAS with these instructions. Please make sure that you read the entire page carefully. There is also the possibility that you could unbrick your Kurobox with these instructions.


Building JTAG tools

Building the JTAG tools varies depending on the platform you use. Refer to Umino's installation page (in Japanese) or The Google translation of the page for building and installation instructions for several popular flavors of Linux.

In general, you need to move into the include directory and do a ./configure and make install and then move into the jtag directory and do a ./configure, make, and make install as root. You will also need to copy the data/motorola/mpc8241 directory to /usr/local/share/jtag/.

You can start JTAG tools with the command "jtag".

Attach your JTAG cable and start your Kuro

The cable attaches to the component side of the board. That means you will need to remove the four screws that hold the board in place to attach the cable. Make sure you align pin one on the header with pin one on your cable (usually indicated by a red wire or mark).

Once the cable is attached, reattach the board, snake the cable out of your Kuro and close the case. You can also just leave the case open, but if you get shocked it is your own fault. Plug in your kuro and press the red button on the back and hold it in. Press and release the power button and then release the red button (no, this does not get you into EM mode). The power, disk full, and diag lights will blink all on and then all off indicating (no, not EM mode) that the watchdog timer has been deactivated.

JTAG tools command sequence to flash the bootloader

The following are the commands to prepare the Kuro for data transfer. This sequence assumes you are using one of the JTAG cables described here and it is attached to the primary parallel port.

Start jtag and execute the following commands at the jtag prompt:

jtag> cable parallel 0x378 DLC5
jtag> detect
jtag> include motorola/mpc8241/1.2 
jtag> endian big 
jtag> instruction SAMPLE/PRELOAD 
jtag> shift ir 
jtag> shift dr  
jtag> dr 
jtag> instruction EXTEST 
jtag> shift ir 
jtag> initbus mpc824x 
jtag> detectflash 0xFFC00000 

According to the Flash ROM page, the flash map is as follows:

start Size (HEX) size contents
0xFFF00000 0x070000 448 K bootcode.bin
0xFFF70000 0x010000 64K HDD status (OKOKOK)
0xFFF80000 0x080000 512 K Empty
0xFFC00000 0x300000 3 MB Linux/initrd

To read the bootloader which is stored in the area described as bootcode.bin type:

jtag> readmem 0xFFF00000 0x0070000 bootloader 

To write the bootloader with file u-boot.bin type:

jtag> flashmem 0xFFF00000 u-boot.bin

Flash Files

Flash files are available at Use these at your own risk.