Is it possible on Linux to use objdump (or any other utility) to fully disassemble an obj file to asm code, modify such code and then pass the asm to as?

The challenge I have with objdump is that it doesn’t disassemble all sections by default and interleaves descriptions/strings that can’t be interpreted/ignored by as.

How can I efficiently do:

1. Get valid asm from an obj file
2. Modifiy such asm
3. re-run as to generate a valid obj file

Again, I don’t need to ‘study’ the asm (objdump is fine for that), I need a valid asm that I can modify and feed back to as.

Thanks!