I am trying to recreate a patch for an ARM binary. As it shows in attached picture, I have provided the before and after sections of file. In patched file, a new subroutine is added in a cave, and then it branches to an existing subroutine that has changed to an instruction.
My question is, how do you recreate such a patch? I know how to edit bytes in IDA, but not sure how to add new ones.