Is there a way to "undo" the hack if something goes wrong?

patterbt

« on: 18 / January / 2010, 08:41:44 »

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I just did my first CHDK hack with my Canon Powershot 850 this weekend, and it worked perfectly. I am very happy with it so far, and especially like that the original firmware on the camera is left alone.

Well I just found out this morning that there is a CHDK hack for my Rebel XTI DSLR. After reading through the instructions on this site, it sounds like installing the CHDK mods for the XTI are a little more "risky". It sounds like after I load in the "testfir.fir" file into the camera, there is no going back. This somewhat concerns me. My XTI is my only DSLR, and the last thing I want to do is brick the whole camera.

Or am I mistaken, that there is so much risk involved in this hack? It would be nice if I could just install a "non hacked" compact flash card into the camera and be 100% sure that the camera will just use the factory firmware (in case I have problems); but I am not sure of this either.

Please help, as I am a total newbie at this CHDK stuff!! Thanks.

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peabody

Re: Is there a way to "undo" the hack if something goes wrong?

« Reply #1 on: 18 / January / 2010, 13:23:43 »

I've read through the entire thread on the 400d/XTi, and have seen this question asked several times. So far I haven't seen a straightforward answer. You can of course remove the stuff from the CF card, but the boot flag changes that resulted from running testfir.fir appear to be permanent. And it also appears that these changes do affect at least one Canon utility program that's used to transfer pictures from the camera to the computer.

So it appears at this point there's no way to return the camera to its original pre-testfir state, even by reflashing the entire Canon v1.1.1 firmware.

But if would be nice if someone who, unlike me, really knows how the 400D hack works could either confirm my understanding or set me straight.

Also, even if the above is true, I wonder if it might be possible to create "untestfir.fir" which really would undo everything that testfir.fir had done.

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hotvedt

106
A540/SX110IS/350D

Re: Is there a way to "undo" the hack if something goes wrong?

« Reply #2 on: 18 / January / 2010, 19:43:31 »

Quote from: peabody on 18 / January / 2010, 13:23:43

I wonder if it might be possible to create "untestfir.fir" which really would undo everything that testfir.fir had done.

This could probably be done the same way as in 350d:

http://chdk.setepontos.com/index.php/topic,4202.msg40082.html#msg40082

Maiohwmai made it possible to turn bootflag on and off for me.

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soon

Re: Is there a way to "undo" the hack if something goes wrong?

« Reply #3 on: 23 / February / 2010, 22:35:50 »

Try flashing the canon original firmware and see.

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Paincookie

Re: Is there a way to "undo" the hack if something goes wrong?

« Reply #4 on: 24 / February / 2010, 01:51:43 »

The original firmware does not change the bootloader

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gafer

Re: Is there a way to "undo" the hack if something goes wrong?

« Reply #5 on: 11 / August / 2010, 00:43:35 »

Bumping up and old thread to see if anyone has an answer on how to "undo" the hack. I wish I'd read this thread before I tried it. Not sure what "permanent" effects I may be dealing with now.

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