I have a piece of firmware that I pulled off an NXP LPC17XX series chip. Through reviewing the processor manual, I was able to identify the entry point of the code and disassemble the code without any issue in IDA Pro. After a short bit of reversing I found a number of functions that are likely printf, sprintf, and their associated helper functions.
I assume that there are of number of other POSIX functions as well as some core library functions for developing for this chip that are included in the firmware that I am looking at.
What is the best way to go about identifying those functions? I assume that there would be some way to develop a FLIRT signature for this, but I am unsure what would be the best way to approach developing a proper signature for this firmware. Any help or guidance would be really appreciated!