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12-21-2012, 12:26 PM   #1
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Modifiying lens EPROM to desactivate SDM and use screwdrive :D

Hello folks,

I know how many of you complain often (very often) about SDM and so on, but, you can all thanks the great hasard that made me click on several link on the great world wide web.

I found a page were two french guys tried (and succed) in cracking some of the code of the EPROM (the chip in lens that contains all the data) of the KAF2 lens, to desactivate SDM on the lens and let the body use screwdrive instead (for 16-50 / 50-135 / 60-250 / 200 / 300) !


following things are in French.

here is the link of the page : Comment reprogrammer votre 16-50mm, 50-135mm ( voir autre) pour ne plus utiliser son SDM ( avec un Pentax K7) - Le site des amateurs de PENTAX

and here is the discussion about the code with some diagrams : [K20D] D

I'll do some translation tomorrow if you want.

the core idea : using the debug menu of the body can allow to reach and copy / paste the EPROM code of the lens.
then they found where the code say "Use SDM : YES" & "Use Screwdrive : NO" is located and the change the value to NO and YES.

If there are some people with knowledge of hexadecimal code and want to work on it, it would be great

12-21-2012, 12:48 PM   #2
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I think you are late:
12-21-2012, 12:55 PM   #3
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Wow, fantastic. This may be old news but I'm so glad I ran across this thread to learn of the old news. Thanks aurele, and clover.
12-21-2012, 06:22 PM   #4
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Original Poster
I didn't see it before posting...

Suddenly dead SDM lens got more value XD

Thanks for sharing Zav, your link is a perfect step by step translation of the french topic we both refers to !


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