That already exists in the kernel by providing "console=ttyS0,9600" or so on the command line. :-)

You don't have to buy a smartphone. This is entirely *optional* and 'classic' will not ever go away.

I could read it with my phone, but yes that's what we agreed upon. I will implement scaling in the coming days

If your embedded board has a HDMI connector, then there is a great chance there is a framebuffer as well. AFAIK, most embedded system only ship a framebuffer and somekind of serial output interface. The real problem in fact is how would you get that framebuffer after a crash occured and you don't have a screen nearby to connect to the HDMI/VGA connector.

They won't disappear, it's going to be optional and will be seamlessly available next to the text crash.

Yes this causes a big output since my (and I suspect yours as well) terminal uses size 12 fonts, but in the crash situation we do it one screen pixel per QR pixel. There is a file called qr_code.png in that folder I gave in the thread, which is the actual result unscaled. It's 147x147 which can fit on every screen I know of.
How to handle textmode is still an ongoing question. We'll first get it working on the framebuffer then maybe we'll find a solution for textmode, if it's even possible.

We are encoding the full Oops, i.e. from the "cut here" to the "end trace" marker. Classic won't ever go away, and we had already created a configuration option called CONFIG_QR_OOPS that can disable this at all. In case your distro or you had compiled it in and you don't want to have QR codes on your screen, I just added a new kernel parameter currently called 'qr_oops', which can as well disable it.