I am using a custom (i686) PC for a product development.
I have created an EFI image that would boot a kernel using grub2.
If I dd the image to a USB drive, plug the drive and then start the machine, the firmware is able to boot. If I take the same image, dd it to the internal SSD drive (connected to SATA Port 1), the system does not boot! Why is this? I tried disabling CSM and secure boot with no results.
I also tried a USB/SATA adapter but, again, with no results.
The same SSD, plugged to my PC with the USB/SATA adapter does boot to grub.
Really, I can't understand what's going on... any hints?
Thanks.
EDIT1: SSD is a common SanDisk Z400s. My computer is a MacBook Pro 2011. The product under development uses an ad-hoc mobo equipped with a i686 processor; boot firmware is Aptio Setup Utility 2.17.1246).
EDIT2: I tried installing ubuntu on the incrimined SSD via the development PC. Well, it gets installed in EFI and it boots correctly! Is it possible the EFI partition needs to have a minimum size for the SSD? The one in my image is just 64 MB, while the ubuntu one is more than 500 MB.
EDIT3: I found out that moving my bootx64.efi to EFI/Microsoft/Boot/bootmgfw.efi does the job. Is it possible the fallback for the SSD drive is only Microsoft/Boot/bootmgfw.efi, while it is Boot/bootx64.efi for the USB drive?
