Remap headphone jack to microphone input?

[Joe]

The Librem 13 version 1 (L13v1) supports a microphone via the 3.5 mm audio jack:

[support] Can't detect headset microphone, how to debug?

The Librem 13 version 1 (l13v1) supports an external microphone via that 3.5 mm audio jack. @mladen told me this and I just verified this with a TRRS (connector has tip, 2 rings, and sleeve) microphone. @mladen told me the CTIA standard is followed for the assignment of roles to the 4 contacts. I don’t know when this functionality was dropped, but it appears to be gone by the l13v3. I don’t know whether the l15 ever had it.

It seems in most Librem 13/15 versions there is no hardware support for a microphone via the audio jack.

Further discussion can be found in this topic:

Record external audio with Librem15rev2

Hi, if I understand correctly, the Librem15rev2 is equipped with a combo port for audio, and I got my headset working with a Y-cable splitting the combo port into a headphone and microphone connection. Now I would like to use the microphone connector to record an external audio source (e.g. with audacity), but I just can’t get it to work! There some source on the web that suggest this should be dead simple (e.g. https://gordonlesti.com/digitize-a-cassette-tape-with-linux/), but in my case, au…