if you go to source.sierrawireless.com and find your module, you should find everything under the firmware section.
For the FX30 it can be found here.
It doesn’t look like they break the firmware components up as much with the FX30 as they do with the WP modules, but that is ok.
First you should turn your .update in to a .cwe.
systocwe wp85 app.update
If you are using the pre-built firmware, you would add your .cwe to the firmware.cwe and generate an spk.
swicwe -o firmware.spk -c stock_firmware.cwe app.cwe
If you are building everything from source, you would need to specify the individual components.
When I rebuild yocto, it generates a file yocto_wp77xx.4k.cwe. The legato build generates a cwe. The firmware package I use comes with pre-built everything else - mcu firmware, carrier firmware.
And I end up with the command I used in my previous post:
swicwe -o my_firmware.spk -c mcufw.cwe carrier.spk yocto_wp77xx.4k.cwe legato.cwe app.cwe
If you are having trouble tracking down any of these components, try running
find -name "*.cwe"
find -name "*.spk"
In the source directory.