rpi4-osdev VS cs140e-20win

GitHub - isometimes/rpi4-osdev: Tutorial: Writing a "bare metal" operating system for Raspberry Pi 4

Basically i can compile and run this -> https://github.com/isometimes/rpi4-osdev/tree/master/part5-framebuffer (and i'm sure every other implementation) just fine but only if i load it with gdb through jtags and then hit continue (c). If i put the exact same kernel (kernel8.img) on the sd and disconnect any hw debugger, it gets stuck at the rainbow spash screen and won't continue. This is wheter enable_jtag_gpio is set to 0 or 1. This makes absolutely no sense to me and i'd love to get an opinion on why it behaves this way and if it underlines a bigger problem.

Something like this would be probably in the top 1% of hobby projects and as far as I can tell, it involves zero EE work: Writing a "bare metal" operating system for Raspberry Pi 4.

This might be of help: https://github.com/isometimes/rpi4-osdev (it’s for the RPi4, but I imagine most of it being applicable to the RPi1).

IMO the best way to get into this type of low-level tinkering is by writing a simple operating system.

https://github.com/isometimes/rpi4-osdev

There are other courses/projects for other boards. The keyword is usually “baremetal”.

For Linux drivers specifically there are training material from Bootlin for instance.

Writing code from scratch. Again, a few options here. You could pick an OS interface and start playing with it, or you could take a more structured approach and follow something like Stanfords cs140e, which would have you write an OS for a rasperry pi from scratch.