Uniden cordless phone - hardware access

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I have accidentally deleted the only existing recording of my
fiancee's mother's voice, who recently passed away suddenly and
tragically (rapid progressing ALS); it was the greeting on her Uniden
cordless phone/answering machine.  (Apparently pressing the 'Stop'
button while listening to the greeting deletes it).

She is devastated, and I feel terrible.

Is there any way to access the phone's memory, perhaps with an
external device?

I understand basically how modern electronics work (I am a software
developer), and so might have a chance - if it's even possible.

I am willing to buy ROM readers or whatever is necessary, if it
doesn't bankrupt us.

Thank you so much for your help; I seriously need it.
Robert Waters

Re: Uniden cordless phone - hardware access

robert.waters wrote:
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My guess would be, there are a minimum of two chips in there. A
microcontroller and a separate flash chip. They're probably both soldered
to the printed circuit board.

At the factory, they may have a provision to tristate the microcontroller,
if they wanted to access the flash. There are devices such as a "bed of nails",
which is a means of making contact with the PCB, for initial programming or
testing. The device is basically a vacuum test jig, with the vacuum holding
the PCB against electrical contacts, for testing or programming purposes.

I haven't seen any hobby devices for reading MLC/SLC flash chips. Your
first issue, would be what kind of pin or contact configuration the chip
has, as to whether it is feasible to use a socket to connect to it. Chips could
be BGA (ball grid array), or some kind of flat pack with leads on the side.
So it may not be particularly "hobbyist friendly", in terms of unsoldering
the thing, so you could fit it into a separate reader device.

You could check with a data recovery firm. Some of them offer to retrieve
files from USB flash sticks. So maybe one of them would be willing to
evaluate the project.

Since I don't know anything about those recording devices, I'd probably
start with a look inside, and a chip inventory including part numbers.
If you look up the chip part numbers, you might get some idea what kind
of flash it is, and then when you get in touch with a data recovery firm,
you can give them some idea what they'll be recovering.

It is open to question, what approach a microcontroller programmer might
use, when it comes to handling flash. On the one hand, they could use pointers
to everything, in which case an "erasure" would mean setting head=tail, and
nothing is physically erased. But the other possibility, is the greeting is
in a fixed dedicated area, and some number of 128KB pages get erased
instantly when you remove the greeting. Then, there is the more minor
issue, of what compression scheme might be used to store the data. But
from the data recovery firm's perspective, their job is done when they
give you a binary copy of the flash contents, and then it is up to you
to reconstruct it.


Re: Uniden cordless phone - hardware access

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Thank you Paul.  I'll start by trying ti id the components on the
circuit board.  I appreciate your detailed comment.

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