Regarding the serial console cable you make your own by following this guide http://www.malinov.com/Home/sergey-s-blog/intelgalileo-introduction. The UART is the only one that display the booting process. I guess you can change this but I’m not sure on the process, I think this is work this way because you use ssh or telnet and these processes start right after boot, I guess you can change this in order to see the booting process but I’m not sure how to do it. If you are going to use Debian I’d suggest you to take a look at this page on how to set up a wireless adapter https://wiki.debian.org/WiFi , there is also a section for USB wireless adapters. I hope this helps you.
I don't know the booting process of Galileo. If I would do this to a laptop, I'd have to enter BIOS and tell it to boot from the SD Card first, or I could do this via linux, changing /etc/default/grub
I will try this.
Also, I'd like to point out that I tried to use dd command to install the debian .img in my SD card, and it created a Partition with a File System. The result was, again, unsuccessful, but I wonder if this is the right path, insted of just plain copy to the root direcotry of the SD Card
Copying files to the root of SD Card is a common way. SD card booting problem depends on a SW version installed on a board and a configuration of SD card files.
As the first step I recommend you to execute the following commands to check board version, firmware version and Linux version installed on a board:
root@clanton:~# cat < /sys/devices/virtual/dmi/id/board_name
root@clanton:~# cat < /sys/devices/virtual/dmi/id/board_version
root@clanton:~# cat < /sys/firmware/board_data/flash_version
root@clanton:~# uname -a
Linux clanton 3.8.7-yocto-standard #1 Fri Oct 10 16:20:19 PDT 2014 i586 GNU/Linux