Upgrading you 3Com HomeConnect Sharkfin/Tailfin cable modem

Warning: I claim no responsibility for what ever trouble you get your self in to (Killing your modem, Cable Company bricking your modem, police arresting you, etc). When flashing firmware, many things could go wrong. Proceed at your own risk.


Update: It seems that more and more ISPs are changing the SNMP community strings. The key to upgrading the Sharkfin (or any other DOCSIS modem), is SNMP. The community strings are the passwords. The default ones are: public (for reading data only) and private (for reading and writing data). If your ISP has changed the strings, you will get a timeout error. If so, try this trick:

Unplug the coax from the modem then reboot the modem. The tricky part is to upgrade the modem while the modem is searching for a signal. There is about a 2 minute window when the modem can be upgraded. The modem will reboot it self if it does not find a signal. Once the upgrade has started the modem will reboot after the upgrade completes.

Also there where a few modems I came across that could not upgrade via the LAN side with SNMP. The upgrade starts to download the firmware then the upload stops mid-way. I do not have a solution to this yet.

1. Download the files: upgrade.zip and select the latest firmware at 3Com's MSO site

2. Unzip the files to your C: drive.

3. Configure tftpd
Launch tftpd, click on the button. Change the "Base Directory" to c:\cm.
Click "OK"

4. Edit batch file.
Change 24.xxx.xxx.xxx to your public IP that your ISP assigned to you. windows9x run winipcfg, windows2000/XP in a cmd prompt type ipconfg.

Save.

5. Start tftpd (if not started already)

6. Start a command prompt (windows9x: start->run->command, windows2k/xp: start->run->cmd)
Type this in to the command prompt: 

               cd c:\cm
               upgrade

Fallow the instructions displayed.

You tftpd status should show something like this:

7. Your modem will reboot if everything went ok. This may take from 1  to 10 minutes.

8. Upgrade HTML Code to 6.04 (After upgrading HTML code there will be a UserID and Password. Userid: User Password: Password)

jayklm@nycollege.edu