The -patch option instructs the compiler driver to run the cmd after the link but before the creation of the additional output file. The macro $(TargetPath) is expanded to the full path of the linked executable.
This example will run the command mypatch replacing $(TargetPath) with myoutput.elf
-patch "mypatch $(TargetPath)" -o myoutput.elf -Fbin
The mypatch command can modify myoutput.elf before the creation of the myouput.bin.