I have my Galileo 2 (1.0.4) which boots from the SD with Yocto, but does not boot with the Rocket disk image. At least there is no serial port available, and the gateway app does not work. When I boot with no SD, or with Yocto SD, the serial port is available (on Windows 10).
On the rocket SD card, per the instructions I have (only) /EFI/BOOT directory off the root, and bootapp.sys and BOOTIA32.EFI in the BOOT directory.
If I add the /EFI directory to the existing/bootable Yocto image, it also does not boot.
Never fails. Post a question, then figure it out yourself 5 minutes later. I figured it out, I needed a FTDI cable, not mini-USB for the COM port connection. I'm now using the instructions successfully at: