So the way we "fixed" this for our scenario was to pass the custom storage information in curtin to meta_simple(), and set the target device for the image to the block device that coincides with what curtin gets as grub_device from MAAS. I have attached a diff for curtin.
Note, the custom storage info needs to be exposed for systems other then ubuntu in maasserver/preseed.py.
So the way we "fixed" this for our scenario was to pass the custom storage information in curtin to meta_simple(), and set the target device for the image to the block device that coincides with what curtin gets as grub_device from MAAS. I have attached a diff for curtin.
Note, the custom storage info needs to be exposed for systems other then ubuntu in maasserver/ preseed. py.