16 Apr
2018
16 Apr
'18
1:48 p.m.
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 :)
Thanks,
Jonathan
On Mon, Apr 16, 2018 at 3:01 PM, W2HX via cctalk <cctalk at classiccmp.org>
wrote:
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?