I saw an earlier post on Sierra’s forum about making delta updates that was never resolved:
Where are we with delta update capabilities now? In particular I’m using the WP7702. I see a lot of code in legato that refers to handling delta updates in pa_fwupdate_singlesys.c, but I can’t find any tools for generating them or any example files for understanding the format if I wanted to make them myself. Based on the source code it obviously involves bsdiff or imgdiff.
It seems that this capability would be most useful for the rootfs, kernel, and legato partitions. It would sure be nice to update these without requiring a 40 MB update file.
Thanks for any insight!