LOUP Engineering: Factory & Production Validation · advanced
EVT, DVT and PVT Need Different Acceptance Questions
A prototype phase name is useful only when the team knows what evidence graduates the build.
EVT, DVT and PVT Need Different Acceptance Questions became a separate note because the failure crossed more than one subsystem. LOUP manufacturing scope includes an EVT/DVT/PVT plan instead of treating every prototype as the same kind of sample.
EVT should prove architecture and bring-up; DVT should validate the design against performance, environmental and compliance requirements; PVT should prove the manufacturing process, fixtures and repeatability. Firmware acceptance criteria should evolve with those phases rather than staying a developer bench checklist.
The fix came from assigning one owner to the behaviour and refusing to hide a hardware or network fault with an unrelated firmware workaround. Evidence marker: evt-dvt-pvt.
Hardware programs need stage-specific evidence. Passing a call test is not the same as proving production readiness. The value is not only the fix itself; it is having a repeatable way to prove the same class of failure has not returned.
Project evidence
LOUP engineering marker: evt-dvt-pvt. This note records the design or debugging lesson without publishing device credentials, private keys, customer data or manufacturing secrets.