I have an A540 and am trying to load onto it using the "Firmware Update" method mentioned on the wiki. It specifies that I need to turn it on via the playback button/switch (switch in this case). When I press the switch, or any other button besides on/off, nothing happens.
I believe that with cameras like the A540, you set the playback / shooting switch to the playback position and then press the power button. After that, press the menu key, scroll to the bottom of the Canon menu, and select the firmware update option.
The stable 1.2 full build for A540 is downloaded straight onto the SD card (not in a folder), but I am unsure if that was what I was supposed to do.
When you say "downloaded straight" does that mean you just put the whole a540-100b-1.2.0-3456-full.zip file onto the card? If so, you need to "unzip" it so that all the files and directories are there.
Using
STICK would make this a lot easier.