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Teddy Boom
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join:2007-01-29
Toronto, ON
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reply to mlord

Re: Upgrading Firmware on Thompson DCM475

said by mlord:

So I'm pretty close to hook-up time. Once I get the new 'duino going, the first task is to rip the 02.08 firmware a few times via different sequences, and do binary compares to judge the reliability of the communications. Then try erasing and reprogramming just the 02.08 firmware, and do readback/verify again.

If that all works, I'll get hold of the 02.16 modem and snatch a copy of the latest firmware from it.

Install the USBJTAG software and take a look at how cable modem flash is organized on other modems, it will help a lot. If you need a flash dump from a modem, I can pass that along..

In particular, what you'll find is that some of the firmware will be human readable. Try searching for "DCM" and "docsis" in a hex editor. If you've read the firmware properly you should find strings like that. When my friend read a DCM425 chip for me, the bytes always came out flipped:
If I load 425-1.bin into USBJTAG and then inspect image0 I see the
string as follows:
CD4M525-.2803.-1118032S-.Sib.n

Flip the bits and I get:
DCM425-52.08.31-110823-SS.bin.

So maybe it is all just pairwise swapped?!?!
So I googled around a bit and found HEX Workshop, which conveniently has a byte swap feature. Not long after that I had a working ST52.08.31 image.
»www.hexworkshop.com/

Unfortunately no Sayal in Ottawa:
»www.sayal.com/zinc/zinc_contactus.asp
But there must be an electronics supply place.. Not sure about test clips, but they aren't that obscure, so the odds can't be too bad.
--
electronicsguru.ca/for_sale/Cablemodems


TSI Gabe
Router of Packets
Premium,VIP
join:2007-01-03
Gatineau, QC
kudos:7

That's called Endianness

»en.wikipedia.org/wiki/Endianness

x86 are little endian

While in this case is likely MIPS based which is usually big endian.
--
TSI Gabe - TekSavvy Solutions Inc.
Authorized TSI employee ( »TekSavvy FAQ »Official support in the forum )



Teddy Boom
k kudos Received
Premium
join:2007-01-29
Toronto, ON
kudos:20

said by TSI Gabe:

That's called Endianness

Thanks! I've heard of little endian and big endian before, and I probably even dealt with the ideas a little 15 years ago, but I sure didn't make the connection.

I mentioned that I'm an analog guy right?
--
electronicsguru.ca/for_sale/Cablemodems