I am using Fedora 42 on the Framework 13 with the AMD HX 370 and I’ve also been having issues with external mics not being recognised by alsa. Not even on a live USB with Ubuntu 24.04 or Fedora 42, so it’s not a software/configuration issue on my end.
I reached out to support and they sent me a new audio card. Replacing it caused no change, so it’s unlikely it’s a hardware issue. I also triple checked that this headset also works fine on my previous Thinkpad laptop still.
The external microphone in question is this one, which I use as a cable for a Phillips headset: V-Moda Boompro Microphone for Gaming & Communication - Black, wired - 3.5 mm Jack : Amazon.co.uk: PC & Video Games
Out of desperation, because I really need the external mic for work, I tried the workaround from earlier in this thread ([SOLVED] Headset Mic on AMD FW13 running Fedora 39 - #14 by James_Richards) and rebooted. To my surprise, the external mic works now! The internal mic stopped working now, but I can live with that as I don’t need it.
I have found my workaround but I would love to understand what’s going on. From my reading of the thread, Fedora 42 should contain a new enough kernel (and alsa, and pipewire, etc) so that no system tweaks need to be made for external mics to work. I should note that I also tested a USB mic and that always worked, so it’s just an issue with the jack port.