The grayed-out speaker icon on an iPhone 7 or 7 Plus, while you’re making a call, is one of the most subtle but frustrating errors you can encounter. Why is your phone blocking this one way of speaking into your phone, or sometimes stalling on startup, but otherwise seemingly fine?
The answer involves an integrated circuit (IC) audio component, moving around slightly inside your phone and becoming unseated over time from normal use. Apple should be aware about the issue at this point, sometimes called a “boot loop disease.” It’s an issue that one repair shop still hears about “everyday from all over the world.” But even with this knowledge, you’re very unlikely to still have a warranty on an iPhone 7 or 7 Plus by this date. Luckily, this issue is a known entity in the repair field, and technicians who work in microsoldering can fix it.
An inaccessible, grayed-out speakerphone icon on your iPhone 7 or 7 Plus is the most obvious issue with a faulty Audio IC. You might also see the Voice Memo app icon grayed out, or refuse to start up or record. Your phone itself may take a long time to boot up, or seem stuck on the Apple logo, although you can often click the home button to get back to your apps.
The issue is that the Audio IC chip has come loose from the main logic board, usually on just one pad, but that means the iPhone cannot access the speakerphone for calls or voice memos. By running its typical self-checks on boot-up, the phone is stalled checking the Audio IC, which is present but has this partial issue. Microsoldering expert Jessa Jones, whose shop confirmed the ongoing nature of this issue, explains the problem in detail in an iFixit Answers post:
The C12 pad for the master clock line of the audio ic chip on the logic board gets stretched/lifted/pulled/weakened simply from normal use of the phone … [T]he iPhone logic board is screwed down into a relatively flexible/bendy housing and this causes the logic board to experience flexion forces that it can’t handle. (Similar in concept to bending a paper clip back and forth a few dozen times.)
In other words: one or more of the soldered pads that hold the audio chip in place, already weakly attached, have come loose through very small amounts of bending and stretching force.
You can try asking Apple to repair or replace your phone. Some replies on forums (Apple discussions, Reddit) suggest that Apple knows about this issue, and has offered some customers replacement phones. Given that the iPhone 7 and 7 Plus were released in the fall of 2016, however, there may not be many replacement phones to give customers, or much sympathy for the issue to begin with.
Those with skills in microsoldering, however, can readily fix the problem, and ensure it does not happen again. This entails removing the chip, fusing an extremely tiny wire around the faulty pad to strengthen its connection to the board, and then re-seating the chip. You can watch Jessa Jones fix an iPhone 7 with an Audio IC issue on a livestreamed repair session:
Apple device data recovery pro Frederico Cerva doesn’t go into quite so much detail, but generally walks through the issue:
SoCal Digital Repair shows how the repair is done in a blog post.
Look for a repair shop in your area that offers microsoldering work. If you can’t find one locally, consider mailing in your device for service to a reputable shop. While it’s not as easy a fix as a battery or screen replacement, it is a known issue that can be fixed and make your still-good iPhone 7 work for you once more.