You probably failed to make your card bootable. This might help you. BTW I have never used the download link on EOS card, it is a new feature.
When you use EOScard make sure that:
1. You have the necesary files in the SD card: *.fir file (only if you need to set the bootflag on that camera; this process to be done only once), autoexec.bin file, plus the ML directory.
2. The Utility recognizes the card by identifiying it in the box next to Refresh.
3. You select the EOS_DEVELOP check box
4. You select the BOOTDISK check box
5. Under Content, make sure EOScard recognizes: DCIM folder, autoexec.bin file, ML folder, and if required (to enable the boot flag on camera) the fir file. When EOScard recognizes all of those files it should give you a check mark or something like that.
6. Press the Save button.
7. Look on the bottom of EOScard and should give you a confirmation that the card was written, ie. write successful.
I recently read about another situations with the newer EOScard utility in which the automatic function brought the files to the SD via internet connection. I am not familiar with this function but Pelican seems to more about it since he created EOScard utility. Anyway the issue was that EOScard utility had downloaded some files plus there were already some files in the card, the user noticed that in the fir file area it showed like 2 files so the user had to select the correct fir file for the EOScard utility to properly prepare the card! One of the files was for Mac and the other was for windows.
Also on most cameras, except 5D3, if you enable the camera bootflag via firmware update, and then do it again you will be disabling the bootflag. In the 5D3 you cannot disable the camera bootfalg. It is and ON-OFF process, so if you have a camera working and set the camera flag using the *.fir file you will be disabling the flag in the camera and ML wont start.
So remember to make a card bootable use EOScard utility, and to set the camera flag use *.fir file and do the firmware update.
