Theoryshare - The Broadband Experts

This tutorial details the process of modifying a RCA DCM315 cable modem with the Blackcat USBJTAG.

Whats Required:

RCA DCM 315 Cable Modem (Made in China / Plastic Bottom) - Metal bottom made in Taiwan modems require a different tutorial

Blackcat USBJTAG Programmer - Available Here

SB5100 (BCM3348) Firmware Image (Sigma X2 142 by Fercsa used in this tutorial)

SB5100 Modified Bootloader (SIGMAX-BL_v2.6-LITE.bin used in this tutoiral.)

Blackcat USB Software Package - Available in the Downloads section of the site

Step 1. Install Blackcat USB Drivers on your system.

From the downloads section of the site download the latest Blackcat USB package, and install the drivers for the Blackcat USB after being prompted to do so by Windows. If you are given warnings about the driver being unsigned install the device driver anyway.

Windows Vista Users: You must complete step 1a

Windows 2000/XP Users: Proceed to step 2

Step 1a. For those using Windows Vista the firmware on your Blackcat USB board must be updated, using the AVR software in the blackcat package.

To perform this upgrade follow the instructions in the UpgradeReadme located in the BCUSB Update folder of the Blackcat USB Software Package.

Step 2. Connect the Blackcat USB programmer to your Motorola SB5100.

Connect your Blackcat USB Programmer to your RCA DCM315 as shown in the picture below, then connect your RCA DCM315 to AC Power.

Step 3. Open Blackcat USB and make sure that your modem has been detected correctly.

A successful result will appear like this

An unsuccessful result will appear like this

If your device drivers are installed incorrectly, or your Blackcat USB is not detected by your PC the result will appear like this

If you have a successful result continue to step 4, if you are unsuccessful check your connections and restart the Blackcat USB application.

Step 4. Update your modem's firmware

To modify your RCA DCM315's firmware using Blackcat USB click the Motorola SB5100 tab at the top off the application, then click change to update your firmware. Then select the firmware that you want to update to in the dialog box, and the software will begin updating your cable modem. This process takes about 5 minutes, and as seen below you can watch the progress of the flash. Once this is done immediately and without restarting your cable modem change your modem's bootloader to SIGMAX-BL_v2.6-LITE.bin.

Step 5. Reboot your cable modem and check to see if your new firmware has been installed. In this tutorial Sigma X2 was used and below you can see the successful result at http://192.168.100.1:1337

Terms of Use:

THIS TUTORIAL IS INTENDED FOR THEORETICAL USE ONLY, USE ON PRODUCTION SYSTEMS MAY VIOLATE YOUR ISP's TERMS OF SERVICE. THEORYSHARE TAKES NO RESPONSIBILITY FOR YOUR ACTIONS. THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. THIS SOFTWARE IS INTENDED FOR EDUCATIONAL USE ONLY AND MAY BE ILLEGAL IF USED IMPROPORLY. USERS ASSUME FULL RESPONSIBILITY FOR THEIR ACTIONS.