...I'm using SDM and swapped partitions in camera menu before taking the cards out to put into a card reader...how do I swap the partitions back so that the camera sees SDM again on boot up?...
The majority of folks using CHDK probably setup their SD cards with the 1st partition as a bootable partition (with CHDK files) and put the photos on a 2nd larger partition. The CHDK menu swap option is handy when you get ready to offload your photos & movies. You just need to swap back to the original bootable partition before re-inserting in your camera to reboot - usually done on the PC using the SDMINSTE.EXE mentioned by @waterwingz.
What do you do if the computer you're using doesn't have SDMINSTE.EXE or the ability to swap back to the bootable partition? Many CHDK users place a copy of SDMINSTE.EXE on both partitions so no matter which partition you are using with the PC you'll be able copy SDMINSTE.EXE to the PC and swap to the bootable partition.
There is also another option with SD cards 8G and smaller. You can setup dual bootable partitions (maximum of 4G per partition). There are several advantages to using dual bootable partitions, but the most important is it won't matter which partition you have selected, the camera will always load CHDK from the SD card. I have multiple SD cards that use both setups, but I probably use the dual bootable partitions setup about 95% of the time.
I created a tutorial in September 2010 that might be of interest - not much has changed except the method for creating the badpixel file. It explains various ways to setup SD Cards for CHDK (including a section on how to setup dual bootable partitions). The tutorial has lots of photos to show what you should see at each step.
http://hotfile.com/dl/104082286/06e667c/Installing_CHDK_on_SD_Cards_(Windows_OS).pdf.htmlI suspect that SDM and CHDK use partitions the same way, so in the section of the tutorial where it mentions copying CHDK files, I'd copy the SDM/CHDK files. It should be easy to test on a separate SD card to see what its like. Good luck!
