EZ Flash how's it work with DSi?

If someone could help me or direct me to a similar topic-I saw the video of how the EZ Flash Vi can bypass 1.4 firmware, but is it for real? How can putting the cartrige in ds lite and then dsi just automatically make it work? i want to know becuz i have DSTT and im gonna buy EZ Flash if I know for sure it will let me play on my DSi again. Thanks for any help and sorry if this is a repeat topic, I couldn't find anything similar.

Putting it in the DS Lite allows you to upgrade the Firmware to a 1.4 compatible version.Once the firmware on the EZFlashVi is upgraded to the compatible version, then you can use it on your DSi.

But are there specific things I have to do to upgrade it or do i just put into the ds lite, run it, and turn it off again and place into dsi?

Pretty much.

can i do it on a dsi version 1.3? if so, can someone tell me or post a link to how to do it step by step?

Ya you can still do the update as long as the firmware is before 1.4
I did it myself