iPhone 7+ verified at Apple Store twice, passing all hardware checks by a genius, refuses to move past black screen with apple logo. Started having issues one day with phone calls (network, whatsapp, facetime) being completely mute on both ends. Then extended to voice memos app, and whatsapp voice notes, saying that no microphone was recognized. Then, when attempting a factory restore, phone locked itself up on black screen with apple logo. After several days of even failing to get to restore mode, managed to get phone back to work, only stalling a backup (if i attempted to set up as new phone, it would lock itself up again), but all issues with calls and voice notes remained. Then it would work for a some hours and lock itself up again on black screen. After last checkup on apple store, where they managed to set it up as new phone after having issues getting it up, they turned it off, and when i tried to turn it back up the same day, went straight to restore mode, and hasn't gone up again. Today, an "Error -50" was displayed on itunes after restore was "successful" but iphone itself remained with black screen with apple logo. It seems to reboot itself periodically from black screen to black screen, and home button is responsive. If ANYBODY has any idea of what I could do to not entirely lose an apparently "perfectly functional phone", i'd appreciate it. Apple Store says that if hardware is ok, then phone is ok. Software is updated to latest available, as well as itunes on the computer.