jimage
jimage
adds the creation of the factorydefault
image target. It also adds creation of two ID-variables in two
separate files to the files target.
The jimage is a binary image of the file system mounted on /mnt/flash/ used for restoring the writable filesystem of the product to its original state.
id is a string called the jimage ID. It is
written to both /etc/release and
/usr/etc/defaultfiles/jimageid (i.e. one file in
the read-only file system and one file in the writable file system) as
the value of two shell variables (JFFSID and JIMAGEID), which are
compared on system boot to determine if automatic upgrade of the
writable file system is needed. If id is
not specified, then a default ID is generated from the information
specified with release
(3).
When a new release of the product is built, id should be changed if the writable file system of the old release will not work with the new release.