1 Bare Metal Embedded C Programming Mini Course
Recommended for working without an IDE on ARM microcontrollers, covering startup code, linker scripts, makefiles and the build and debug process from the command line.
Channel
Fastbit Embedded Brain Academy
2 recommended videos. Channel on YouTube
2 Bare Metal Embedded C Lecture 1: Build Process Explained
First lecture in a Fastbit series, widely suggested for learning how ARM firmware gets built from the command line with GNU tools instead of a vendor IDE.