I'm at a loss to explain that. This works quite well in my netboot testing when I remove MAAS from the equation. You *are* meant to be able to chainload grub from another grub; and the reason why grub can't chainload shim is that you then get the wrong set of shim protocols to properly validate the next binary. This will need more testing; I will need to know what hardware this is and what exactly is the content of the grub configs.
I'm at a loss to explain that. This works quite well in my netboot testing when I remove MAAS from the equation. You *are* meant to be able to chainload grub from another grub; and the reason why grub can't chainload shim is that you then get the wrong set of shim protocols to properly validate the next binary. This will need more testing; I will need to know what hardware this is and what exactly is the content of the grub configs.