"IGNORE microphone for wired headset" not working on Samsung Galaxy S4 running Lollipop

Hi,
I've been using Mikey on my Galaxy S4 for a long time, but it wasn't until I  upgraded to lollipop that it started to work incorrectly.
When I insert the Mikey device into the headset jack, the Mikey app asks whether you inserted de Mikey or not, by selecting the first choice, the app tricks the smartphone into "thinking" that there's no headset connected, so the smartphone's built-in mic and speaker work properly...
Well, that's not happening since I upgraded to Lollipop, the smartphone speaker is working properly, but not so the built-in mic, it's muted (when recording a video or saying the "ok Google" hotword, for example)
that's the reason I installed SoundAbout, to ignore the wired headset's mic and make the smartphone use the built-in mic, but with no luck, the app is not able to accomplish that duty...
I've tried the app on a Galaxy S5 running Lollipop, and it seems to work fine, is it possible that there's a bug when using it on my S4?
Please, let me know if you are or will be interested in solving.
Thank you.