PhoneVitals › Restore error codes › Error 40
iPhone restore error 40
What iTunes and Finder are actually telling you, and which component to look at first.
Error 40
Check the NAND memory/controller and its solder joints — NAND chip most likely dead (confirm via ASR output in restore log) - board-level; old sn0wbreeze bug also produced it
Most likely: NAND storageStop guessing which part failed
PhoneVitals reads the phone's own telemetry over USB and names the failing component with the evidence attached — battery gauge records, decoded kernel panics, board-level suspects. Your first device scan is free.
Download for WindowsGuides for the bench
What an iPhone will tell a Windows PC over USB
Reading iPhone kernel panic logs
Diagnosing an iPhone that won't charge
Checking the real battery cycle count