Can you confirm something...
You say you extracted the image to the root of the card, but that's not normally how you get the image onto the SD Card.
The image file contains a complete image of the file system for the SD Card, it is not just a file to be copied to a card with an existing file system.
It's a bit hard to explain, but basically the image file contains all the internal gubbins of a complete file system, not just the files themselves.
So you need to 'burn' the image to card.
On Linux, Unix and Mac OS X this is easy, you use the 'dd' command.
On windows it's a bit more tricky - you need to use some software that can 'burn' SD cards from raw-image files.
What OS do you have on your PC?
You are using the old version of the IDE which includes firmware 782. Please download the new version of the IDE which will include version 1.0.0. You can find it here:Software Downloads - Drivers. Notice they use the same version number. 1.5.3. Also take a look at this post, problem about galileo booting from sd card. It stops booting at the same message as yours.
Sorry - just realised that you already stated that you are using a mac!
In that case, to 'burn' the image to the SD Card you'd do the following:
Insert the SD Card into the card reader slot. If it mounts and appears on the desktop 'eject' it.
Now, open a terminal window.
This will give you a list of all the attached drives (including the SD Card, even though it is now unmounted).
Take a note of the correct card - you can tell by it's size and contents as listed in the output from diskutil. On my system it was "/dev/disk1"
Now move to the directory where your image file is, and type:
dd if=<image_file_name> of="/dev/diskxx" bs=8m
Where /dev/diskxx is the correct path to your SD Card, and <image_file_name> is the name of the Galileo image file you unzipped from the 7z file.
This will burn the image to the SD Card. It may take an hour or more.
I was following this blog post marxy's musing on technology: First look at the Intel Galileo embedded linux board which said to run:
7z x LINUX_IMAGE_FOR_SD_Intel_Galileo_v188.8.131.52z -o/Volumes/BOOT
doing ls -l of /Volumes/BOOT gives what looks like the correct directory structure:
drwxrwxrwx 1 meatplatter staff 4096 19 May 19:33 boot
-rwxrwxrwx 1 meatplatter staff 1974224 14 May 23:38 bzImage
-rwxrwxrwx 1 meatplatter staff 1695878 14 May 23:38 core-image-minimal-initramfs-clanton.cpio.gz
-rwxrwxrwx 1 meatplatter staff 279670 14 May 23:38 grub.efi
-rwxrwxrwx 1 meatplatter staff 314572800 14 May 23:38 image-full-galileo-clanton.ext3
I'm running on a mac (my PC is in bits). Do I need to use the dd command instead? I thought I'd need a proper disk image for that rather than the zip Intel provides.