Giulio Zompetti

5/ At the end of this stage, the models ‘surviving’ tests enter in the Development phase, which we know has different stages itself: ENGINEERING Validation Test (EVT), DEVELOPMENT Validation Test (DVT) and (mass) PRODUCTION TEST Validation (PVT).pic.twitter.com/VNvnNVzQP0

6/ Standing to some reports from a former Apple employee, these stages are not always strictly identified, and it’s not always clear when a certain products leaves a stage to get into next one. We can try to group up Apple’s protos by some common aspects linked to their stage.pic.twitter.com/ZK0LVD8Z7O

7/ During EVT and DVT stages, all devices show up with a shape similar to the production units. They are provided with a Silicon that has main security features open to debug with SWD/JTAG tools. A parameter represents the security specs of each Silicon: CPFM (ChiPFuseMode).pic.twitter.com/qOBHccWQAe

8/ CPFM set to 0x00 allows both AP and SEP to be debugged, 0x01 allows debugging just on AP and 0x03 restricts debugging. Externally, all regulatory is missing or replaced with XXX. A serial number is printed along with a project identifier on the back/side of the device.pic.twitter.com/5jzPSLo9TV

9/ Sometimes, the project identifier is reported on the screen frame too. Though is very rare, they can be still found with red plastic stickers that serves as lightning port protection, as well as other stickers that describe the unit assembly hardware specs.pic.twitter.com/Vsz93HGa1e

11/ Externally, they look very similar to production units, and may differ for just stickers and red plastic covers for the lightning ports. Up to this point, I’ll take a break. These informations came from my personal researches, they can be wrong/incomplete.pic.twitter.com/jYsIOM4JsB