The device has reportedly entered the PVT (Product Validation Test) stage, used to detect any potential faults that could affect the assembly process.
If everything is ok, mass production of the iPhone can already start.
However, the report doesn’t mention if the validation phase includes only one model of the iPhone 6 or both.
Last month it was reported that Foxconn had begun mass production of the 4.7-inch iPhone 6, with the 5.5-inch phablet version set to enter manufacturing stage in the second week of August.
Apple is expected to be unveiled at an event on Tuesday, September 9.