| What's Going On? |
There are
46 guests on-line
|
|
|
|
|
|
Do our DMEs have a limit on the number of reflashes?
I remember my SA telling me at some point that the DMEs in our cars have a limit on the number of times they can be reflashed. The number was pretty low. He said it is 10.
Now I was very skeptical when I heard it but I would be interested to know if this is just misinformation or there is some truth in it.
Thanks,
Florian
| | Reply » Do our DMEs have a limit on the number of reflashes? |
From what I hear, some of our cars are on version 40 something as far as software. I doubt it.
| | Reply » Do our DMEs have a limit on the number of reflashes? |
All flashable memory devices have a limit on the number of times they can be reflashed. I don't know off hand what the numbers are for the various types of media, and I don't know what kind is being used in our cars, but 10 sounds quite low to me. Perhaps the reason for such a low number (assuming it is correct) has more to do with the rest of the DME electronics rather than the memory module itself.
| | Reply » Do our DMEs have a limit on the number of reflashes? |
Quote: I remember my SA telling me at some point that the DMEs in our cars have a limit on the number of times they can be reflashed. The number was pretty low. He said it is 10.
Now I was very skeptical when I heard it but I would be interested to know if this is just misinformation or there is some truth in it.
Thanks,
Florian | Following was posted at Roadfly in January.
> As usual BMW gives you 1/2 the answer to a non-question.
>
> (Well, it's an issue for techs as will become clear, but a total
> and complete NON-issue for most owners)
>
> Let me rewrite the above statement in a more correct fashion.
>
> (I'll capitalize the important bits)
>
> "The ECM contains a soldered in Flash EPROM which can be CHANGED TO
> AN UPDATED SOFTWARE **VERSION** BY PROGRAMMING" a total of 13 times
> after the initial programming".
>
> There is NO limitation on flashing the same version of software
> with modifications, except the MTBF of the flash itself which is
> many orders of magnitude beyond "13". Think 10,000 to 100,000+
>
> I have DME's not 3 feet from me as I type this that have been flashed
> over 2000 times since 1997. Mostly for Car Club demonstrations and
> internal R&D.
>
> The limitation to 13 "new versions" of software comes from this
> simple fact. Every time BMW (not me, not the Shark Injector,
> not Dinan, etc) reprograms software, they update something called
> the AIF. In German Aenderungs Info Feld (Change Info Field) to
> update the actual/literal PART NUMBER of the control unit.
>
> (FYI: German folks.. had to use Ae to represent A umlaut 
>
> The area into which they write the AIF is not erasable by design
> and is 644 bytes in length. (actually it's a bit larger, but not
> larger enough to make a difference)
>
> Each AIF entry takes up 46 bytes: 644/46 = 14
>
> So, including the first time a "brain dead" control unit is programmed
> there are a total of 14 programings that can be done to change the
> programmed PART NUMBER.
>
> There is your limitation, which means nothing in the overall scheme
> of things.
>
> Hope this helps.
>
> Jim Conforti
| | Reply » Do our DMEs have a limit on the number of reflashes? |
Thanks Ron,
This is very informative indeed. I wonder why BMW chose to take this path. It clearly gives them the ability to have a history of all changes (major versions of software ever flashed). And also protects the AIF because it cannot be overwritten. But this might be a bit of a limitation for future cars, with more electronics that will potentially need to be updated with a lot more versions than 13. That there are more efficient ways to achieve the same like digital signatures or other methods is no question. Very interesting nevertheless.
Florian
|
Page 1 of 1 |
1
|
|
|
Menu
Do our DMEs have a limit on the number of reflashes?