How it started My iPhone 6s Plus is barely usable now. It takes several seconds for my touch to register. This only began at the end of December while I was listening to audio messages. I was in the middle of responding to one when the “Low Battery” notification popped up. I dismissed it because I wanted to finish my text. I still had 20% juice left. To my surprise, when it played the next audio clip, it started lagging very badly. I didn’t get to send my iMessage. I figured I’ll charge the phone for a while, thinking it’ll help. It didn’t. It was still unbearably slow so I restarted it to no avail. Next, I decided to drain the battery all the way down to 0% by playing YouTube clips on auto-play. Opening the app took me a long time, but the audio playback was fine. I recharged the phone all the way up to 100% but it still didn’t fix the problem. Trying to fix it Running out of options, I reset my device to factory settings and did not restore from backup, fearing it might reintroduce the bug. The result is the same—lag like there’s no tomorrow. Even in the setup screen. Frustrated, I put the phone in recovery (DFU) mode and restored the firmware using my Windows laptop. It didn’t fix anything. The phone was still slow. Key notes My phone worked phenomenally before all of this. I barely even use it because I have a secondary phone for work. It has never been dropped, water-damaged or exposed to the elements. It looks as pristine as the day I bought it. The phone is running iOS 14.3 when the issue started. It is still running that software now. My battery capacity is at 91% with the phone saying it’s in “Peak Performance Capability.” It has been diagnosed by Apple Support via chat and everything came back clear. No hardware problems were detected. The phone sometimes comes back to its “original” or “intended” speed when I’m trying to unlock it with a passcode. As soon as I get to the Home Screen or swipe right to open Camera, however, the phone starts slowing down again. When the issue first started, my cellular service and Wi-Fi started acting up. The former displayed “No Service” while the latter took too long to connect. The bug seems to have been fixed by the DFU restore. I have a couple of things in mind: another DFU restore when iOS 14.4 comes out or a battery replacement. Beyond that, I don’t know. I’m at a loss. I know it’s an old phone, but it’s never acted this way until that one day I decided to listen to the voice messages. Has anyone ever experienced this? Any recommendation? Thank you so much.