[Xperia Z1 Compact Q&A, Help & Troubleshooting] jujube123:
Hey folks,

So I have a problem with my Sony Xperia Z1C (D5503), and would appreciate some input on my theories as to how to fix it, at which I have yet to be successful.

I live in China, and I bought my lovely device on Taobao a few months back for a very discounted price (risky, of course, and to be certain this is where the issues stem from). I purchased the Hong Kong version instead of the Chinese version, because the Chinese version is built to block Google Play by default and comes with a bunch of junk apps. Anyway, I was stupid and didn't get a chance to use it before the seller's 7-day return policy was up, so it was too late for a return after I found out about its issue.

The issue is this: when I receive a call, the caller cannot hear my voice. Not that it's completely silent, it's just muffled and quiet. I've tried various things, turning on and off the Microphone Noise Suppression option, adjusting the caller's sound options, but nothing; it seems there's a defect with the microphone. When I switch to speakerphone during a call, however, there are no problems. On a related note, the same thing is true when I use apps like Skype and particularly WeChat: if I send someone a voice message, they can barely hear me. Only when I use a headset are there no problems. So, to continue using this phone, I've succumbed to bringing my headphones around with me and plug them in when I receive calls or have to send a voice message.

So the microphone's screwy? Interestingly, when I record with other apps, like the Sound Recorder app, there are no problems. It picks everything up perfectly. It must be recording on "speakerphone" for this app, if that makes sense; right?

Anyway, I was wondering (hoping) if the kernel loaded on my phone has anything to do with it. It's the stock kernel but one that seems to be used more for the Xperia Z1. Since I'm mentioning it, here are all the specs:

Model: D5503

Android Version: 4.4.4

Baseband version: 8974-AAAAANAZQ-10270054-61

Kernel version: 3.4.0-perf-gaee6e5a BuildUser@BuildHost #1 Thu Oct 9 09:14:33 2014

Build Number: 14.4.A.0.157

Anyway, I still have this hope that the problem is fixable. I am inclined to wait for the rollout of Lollipop for the Z1C, but that could be months, and this has been going on long enough as it is.

I'd appreciate any input, especially if you think I'm on (or not on) the right track thinking that flashing a new kernel may make a difference, assuming it is a conflict with the firmware. Or, perhaps I should just accept that I was sold a defective product for a decent price (I mean, everything else is working OK...).

Should also add, running the service diagnostic test for both primary and secondary microphones provides clear, audible results.

A few additional details, that may be of interest: my phone is rooted, with SuperSU as the app. The stock version of the app is a system app, but when I update the app, it loses its system app status and also does not successfully update the binary. I couldn't install busybox for the longest time but was finally able to do so through the advanced root options FlashTool. This is interesting, I think. Also, there is no recovery mode.

Thanks for your time!