you can decrypt it with Openbox_Toolbox_V1.1 it will let you add and extract different sections of the abs file and it will also do checksums for you it shows up as a virus with some virus scanners but appears to be safe on my pc
I didn't see anything new in the toolbox.
I already had the mst firmware tool and partels firmware tool,neither will decrypt firmware.
You can extract parts of the firmware with any hex editor,but they will still be encrypted.