Rudolf J Streif
A not so well-known feature of the WIC bootimg-partition plugin is that it can install files into different partitions. For that the variable IMAGE_BOOT_FILES has to be defined as one of the following:
IMAGE_BOOT_FILES_label-<partlabel> = "..."
IMAGE_BOOT_FILES_uuid-<partuuid> = "..."
The plugin will then use either the partition label or the partition uuid from the WKS file "part" directive to look up the correct file list variable.
This code snippet from the plugin (poky/scripts/lib/wic/plugins/source/bootimg-partition.py) is supposed to do the trick:
50 boot_files = None
51 for (fmt, id) in (("_uuid-%s", part.uuid), ("_label-%s", part.label), (None, None)):
52 if fmt:
53 var = fmt % id
55 var = ""
57 print('var: ', var)
59 boot_files = get_bitbake_var("IMAGE_BOOT_FILES" + var)
60 if boot_files is not None:
However, the function get_bitbake_var() from poky/scripts/lib/wic/misc.py uses the the WIC environment which is created from the WICVARS variable by the poky/meta/classes/image_types_wic.bbclass. WICVARS is defined at the beginning of the class and contains all bitbake variables relevant to WIC. It of course includes the plain IMAGE_BOOT_FILES. When the class creates the environment (do_rootfs_wicenv) is simply splits WICVARS and looks up the variables one-by-one in the DataSmart dictionary (d.getVar(<varname>). Since this is a key lookup it will not match any variables for IMAGE_BOOT_FILES_label-<partlabel> and/or IMAGE_BOOT_FILES_uuid-<partuuid>.
For this to work there should be a lookup in DataSmart that supports getVar() with a wildcard or "starts with". I am not all into the details of DataSmart and maybe there is something like this already and I just don't know about it. Hence the question here before I start hacking a kludge into the image_types_wic class.
Rudolf J Streif