I have used CHDK on my ixus 50 with no problem so I have a basic grasp of the system.

I have made a bootable card, using cardtricks, for my S90.

When the card is unlocked, the s90 behaves as it should. If I leave the card out and switch on, I get a message telling me so. If I lock the SD to autoload CHDK and put it in the S90, it will not switch on even if I hold the button down for a while. It will not then switch on with any other card until the battery has been disconnected.

I have tried this with two SDs of different size and manufacture but with the same result.

If I take the SD which works in the ixus 50 and put it in the S90 (obviously with wrong build) it will not switch on if the card is locked.

If I take the SD prepared for the S90 and put it in the Ixus 50 (again with the wrong build) the ixus will not switch on and will not recomence working until battery is removed.

This seems to indicate that the S90 will not switch on because the wrong build is on the card but I have checked this carefully a couple of times now.

Can anyone help me?
I