How can I disable the iPhone's microphone?

I would like to disable the internal microphone for everything. My device is jailbroken and I have tried 'Disable Microphone' in MyRepoSpace, however that just gets rid of the Voice Memos app instead of actually disabling the microphone.

Is there a way to disable the microphone, such as deleting the drivers? Or do I have to physically break it?

Deleting mediaserverd from launchdaemons removes all audio and recording. However, it also makes the device hang for several seconds when something tries to play audio.

If security is a major concern, I'd assume that a software hack is not the solution. There still is a chance of malicious software importing code which re-enables the audio functionality.

I read NSA guidelines for Mac OS X 10.6 about disabling iSight on Macs where is was recommened to physically remove the webcam for absolute security.

If you do not want to physically remove your iPhone's microphone, I would try to distort the audio as good as possible - that would leave a spy with imprecise mumbling noises. The iPhone 4 can be muted quite effectively by just closing the hole at the bottom. There is a good chance that closing the hole of the microphone has the same effect. You could apply prestik or hot glue for example.

Poke the mic with a needle a few times and it's disabled physically if your concern is security related... tinkering in software will not help you, even if you could remove the drivers or anything. If an attacker would get control of the device to listen to a microphone stream he will probably also be able to replace said driver.

This is a long shot, but it might fool the iPhone into thinking that it doesn't need the internal mic.

Get ahold of a 2.5mm cable microphone (I had one way back when for my Minidisk player, they're probably still on sale and very cheap) and cut it off, leaving you with only the plug and if needed, something to remove it with.

Because it doesn't have any earphone capability, this will not cause the iPhone to output sound through it (so you still have a fully functional iPhone) but with any luck it'll see a mic input, and turn off its own. Whether this will disable the ambient noise sensor, though, I don't know.

How about connecting a iPhone headset with a broken/disabled/muted microphone? The phone should detect that a headset is connected and will disable the built-in microphone in the phone, but won't be able to get any signal from the headset.

I have a pair of Bose QC 15 noise canceling headphones. They have a switch for the noise-canceling feature which also kills the sound output in the cups. The microphone will work though regardless of whether the switch is on or not. This headset has excellent background noise muting however. I just recorded something with the refrigerator defroster going in the background. The headset mic muted out about 90% of the background noise.