How to make GPL request to manufacturers such as Xiaomi?

Hi, this might be a dumb question. I attempted to search here but didn't get anything, or maybe I was using wrong keywords.

My understanding to GPL and OpenWRT is that the manufacturer being obligated to release build-able source (with certain possibly close source binary blobs outside of GPL). Is this correct?

I attempted to search and found Xiaomi's Android kernel source, however i cannot seem to find their OpenWRT equivalent. Furthermore, when i google Xiaomi's open source request contact info, i did not seem to see any useful result.

May i ask for guidance on how to generally request source from companies like Xiaomi, who uses GPL codes in their product? I am particularly interested in their new Qualcomm based AX6000 router. Thanks!

That's interesting question and i also want to hear some answer of that.

You might want to contact the Free Software Foundation and the GNU Project.