Qualcomm _does_ upstream all their firmware, but vendors usually require a firmware binary to be signed with their keys, which are burned into the SoC. As a result you cannot use Qualcomm's vanilla firmware and need to extract the original firmware as provided by the vendor, otherwise it won't load. This is an actual security feature, believe it or not. Besides, chances are it wasn't even Qualcomm's firmware, but rather Cirrus for sound or display firmware, etc.

I get the hate on Qualcomm, but you're really one LLM question away from understanding why they do this. I should know, I was also getting frustrated before I read up on this.