Have you been able to use your Galileo before? Or is this the first time you use it?
When connecting the Mini-USB do you see some changes in the Device Manager? Could you please share an image of your Device Manager?
I have been able to boot from the SD card (Yocto image installed) and use the Intel XDX IOT Edition to connect to the Galileo and build/run programs.
One data point I did not mention before is that I received the Galileo in a boot camp course and so I am not sure if anything has been changed on the device's firmware. I suspect this is where the problem lies.
When connecting with the mini-USB, there are no changes in Device Manager (a picture would not be very useful ). It is as if that serial port is completely dead. If I use the other cable (TTL header) it is detected and on my computer assigned to COM10.
Have you tried running the UEFI internal shell recovery method? You can check an explanation under section 10 of the next document http://www.intel.com/support/processors/quark/sb/CS-035211.htm. The process uses two files created in section 8, so you’ll need to keep an eye on that.
If you have access to a Dediprog, you can also try to recover your Galileo board that way (this is the easiest way, but not everyone has access to a Dediprog), you can check the instructions under section 11 of the document above.
Some time ago, another user developed a method that he called “Galiprog”, in which a second Galileo device acts as a programmer. If you have a second Galileo board you can follow the instructions from here: https://github.com/xbolshe/galiprog.
Is your issue resolved ?
If yes, could you please share what method you used to solve your problem to boot the Galileo Gen2 without SD card.
Would you describe the problem you have? Meaningful screenshots help a lot for describing problems.