At the moment there are commands to convert one file format to another, but not
to 'merge' or alter them. Some firmware files are containers which can store
multiple images, each with optional id, idx and addresses.
This would allow us to, for instance, create a DfuSe file with two different
raw files that are flashed to different addresses on the SPI flash. It would
also allow us to create very small complicated container formats for fuzzing.
This can be used by writing a `firmware.builder.xml` file like:
<?xml version="1.0" encoding="UTF-8"?>
<firmware gtype="FuBcm57xxFirmware">
<version>1.2.3</version>
<image>
<version>4.5.6</version>
<id>header</id>
<idx>456</idx>
<addr>0x456</addr>
<filename>header.bin</filename>
</image>
<image>
<version>7.8.9</version>
<id>payload</id>
<idx>789</idx>
<addr>0x789</addr>
<data>aGVsbG8=</data>
</image>
</firmware>
...and then using something like:
# fwupdtool firmware-convert firmware.builder.xml firmware.dfu builder dfu
In many plugins we've wanted to use ->prepare_firmware() to parse the firmware
ahead of ->detach() and ->write_firmware() but this has the limitation that it
can only return a single blob of data.
For many devices, multiple binary blobs are required from one parsed image,
for instance providing signatures, config and data blobs that have to be pushed
to the device in different way.
This also means we parse the firmware *before* we ask the user to detach.
Break the internal FuDevice API to support these firmware types as they become
more popular.
This also allows us to move the Intel HEX and SREC parsing out of the dfu plugin
as they are used by a few plugins now, and resolving symbols between plugins
isn't exactly awesome.
