Not needed for script
I thought it's worth to mention...
Edited how ? You need to put the SCRIPT string at the correct offset.
I used Winhex, put SCRIPT to 0x1f0 as written. Then I ran EOSCARD and saw the checkbox was checked next to "SCRIPT" (or whatever, I don't have the program nor the SD card with me currently, but I'm sure you get the point).
Note that you must start the camera in play mode and press SET to run a canon script, assuming the rest is done correctly.
Ahem. I assume this is written somewhere and I've just missed it. Of course I did not push any buttons.
"Cardtricks way" is not a useful description of what you did. If you tried to use the udumpers available from card tricks, there is essentially no chance they will work.
Let's try then it again: I ran cardtricks 1.44, pushed "newDryOS" button, was waiting for it to format the SD card and copy the necessary files; then I put the SD card into the camera, push the play mode button, counted slowly to 30, turned off camera, push the SD card to my computer, start Cardtricks again and push the "strings" button. In short, I did exactly what you have mentioned.
Note that if you are not reasonably skilled in C and assembler, there's no need to try to get a dump, since you will not be able to do a port anyway.
There are quite some of us have been waiting for A490 port for more than a year now. What is needed? The proper camera, motivation and time. Apparently no one had all these together for a year so I decided to do my contribution. What I'm asking for is just some assistance from the busy gurus. The worst thing to happen is that I'll stuck somewhere but until that point the process will be documented via the forum and someone can take it over. I'm not a skilled C or assembly programmer indeed but I have to start somewhere and at least I'm interested in porting.
So thanks for the tip with SET button, I'll try it as soon as I can.