8085 Dissasembly?

systems_glitch systems.glitch at gmail.com
Mon Apr 16 15:48:11 CDT 2018

IDA Pro will do 8080/8085 and is very nice -- especially if you have no
source and are having to reverse-engineer the whole thing yourself. The
commercial version is expensive, but there's a free version. I don't
remember if the free version includes 8080/8085 mode.

The strings may be packed ASCII, to save space. There were a few methods of
doing this.

If there's a checksum it's not inherent to the CPU. There would need to be
custom hardware on the board to enforce a hardware ROM checksum; otherwise,
it's left to software and you can easily update that :)


On Mon, Apr 16, 2018 at 3:01 PM, W2HX via cctalk <cctalk at classiccmp.org>

> Hi friends. I have a 1990's vintage commercial radio system that uses an
> 80C85A CPU. I am looking to hopefully modify the firmware to make some
> small changes in its behavior.  The firmware is contained in two EPROMS.
> Can anyone recommend a decent disassembler to use with this? Preferably
> something that ran in windows 10 or windows 7? A dos box would be fine too.
> Also, I looked through the dumped contents of the EPROM. In the past I
> have seen EPROM ascii dumps where most is unintelligible to the naked eye
> but typically text messages give to the users during interaction with the
> program are human readable. In this case, the ASCII dump shows only other
> HEX data.  I believe I read that there is a HEX format and that I might
> need to convert from HEX to BIN before disassembling. Of course, an ideal
> tool would do both if anyone knows such a thing.
> I am not familiar with 8085 stuff but any insight would be appreciated.
> Lastly, I wonder if there might be some kind of checksum check to prevent
> tampering. Is there a common way this is handled in 8085 world? Or is it
> entirely programmer dependent?
> Thanks for your time
> Eugene W2HX?

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