Re: identifying an unknown eprom content

From: Hans Liss <Hans_at_Liss.pp.se>
Date: Thu, 27 Aug 2020 13:17:35 +0200
Message-ID: <674ac036-fb28-20a2-63ca-5fbb3b052bc9_at_Liss.pp.se>
If you can share it, send it as a zipped attachment to the list, and 
more people can take a look!

/Hans

On 2020-08-27 13:14, didier_at_aida.org wrote:
> I know very little about this eprom
> it was given to be by commodore maintenance about 30 years ago
> according to the label it was supposed to work on a network board 
> installed in a 8032 motherboard
> obviously it's not the case
> I'm thinking to a c64 cartridge in ultimax mode (booting in $E000)
> I'm trying to get a better disassembly and some clue to go further
>
>
>
>
> On 27/08/2020 12:56, Francesco Messineo wrote:
>> Hi,
>> just a suggestion: when you reverse engineer some unknown firmware,
>> you NEED also to have a complete schematic of the system before you
>> start.
>> So if you don't have a schematic, you need to first reverse engineer a
>> good schematic.
>> I tell you that from my own experience on reverse engineering these
>> kind of old and undocumented boards.
>> The code starts to make sense (and you can start making sense of it)
>> once you know where RAM/ROM and whatever else (I/O) is mapped.
>>
>> HTH
>> Frank IZ8DWF
>>
>> On Thu, Aug 27, 2020 at 12:49 PM <didier_at_aida.org> wrote:
>>> I'm trying to identify an eprom with an unknown content
>>> I was thinking it was the eprom booting the server (a commodore mother
>>> board without screen nor keyboard in an industrial box)
>>> (on the commodore we had a network composed of a server and up to 16
>>> stations)
>>> I have 2 eproms labeled:   pc-central-26-4.bin (8k)  and
>>> boot-poste-3.bin  (4)
>>> the boot-post-3.bin contains the good content...  [the copyright is
>>> present]
>>> what I know on the pc-central-26-4.bin:
>>> - it's a 8k eprom, starts at $E000, the code starts at $E002 before
>>> there are 2 bytes  $00 $BF
>>> - it's 6502 code  (seems written by an amateur)
>>> - there is some code between $E800 and $E8FF so it's not a 8032
>>> - they are writing something around $8000  and also around $0400
>>>
>>> I was thinking that perhaps it was something for a vic20 or a c64 but
>>> I've not really used this 2 machines
>>> any idea of what I can do to identify the machine ?
>>>
>>> I'm thinking to try to check the use of I/O area but I need a better
>>> disassembly
>>>
>>>
>
Received on 2020-08-27 14:01:26

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