Joule cannot boot with an image built on the following sha's: poky: 4b94b49 meta-intel: 8dbd551 The same image boots fine on a minnowboard. the procedure is: 1. build a core image minimal with the machine as genericx86-64 2. burn the hddimg image to an SD card or a USB stick using dd 3. boot it in a joule machine 4. at this point you'll see the image does not show any boot option nor boots at all.
Which bootloader / EFI_PROVIDER are you using? It might require you set EFI_PROVIDER = "systemd-boot"
indeed, using EFI_PROVIDER = "systemd-boot" has genericx86-64 to boot in the Joule board.
The joule requires the systemd-boot loader, closing