downgrade firmware possible? (yes it is possible) - DSLR Hack development - CHDK Forum

downgrade firmware possible? (yes it is possible)

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Offline PhyrePhoX

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downgrade firmware possible? (yes it is possible)
« on: 25 / February / 2009, 06:12:06 »
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just updated my 40d to 1.1.1 (from 1.0.8 ) because i desperately needed a fix that is adressed in this upgrade.

now i noticed that for the canon dslrs, you can have several firmware update files on the CF card and then choose which one you want to upgrade to (see screenshot) - i guess this is for service technicians so that they only need ONE cf card, that contains both their service firmware (to adjust stuff) and the actual latest firmware.
the name of the fir file is not important, as you may see in the screenshot. when you press on one of these firmwares you are shown a screen on where you can choose if you really wanna upgrade from "1.0.8 -> 1.1.1".

Now here's is the question: I updated to 1.1.1, and upon re-entering the firmware update menu i saw it is possible to "upgrade" to 1.0.8 - at least i was asked if i want to do it - i didnt press "yes". i guess the cam would have told me then "hey you are trying to downgrade, no can do!"?
Any experience on this?
Background: If Dataghost somehow someday releases something, it is likely to be for 1.0.8 (thats the fw version he is using), so it might be worth downgrading...

Answer: According to dslr-forum.de downgrading is possible, without any sideeffects. good to hear.

P.S: I tried doing the same on my s3is (having several *.fir files on card), but the firmware update entry is not shown when there is more than one fir file on sd card. but renaming PS.FIR to xyz.fir for example works fine (cam finds it and "updates to it") - didnt know that up to now.
this *might* be important to know when you want to swap/switch between different CHDK flavours, one should rename the extension then, like PS.1IR and PS.2IR and so on ;)
« Last Edit: 25 / February / 2009, 11:14:04 by PhyrePhoX »

 

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