Apple’s first foldable iPhone could be difficult to get hold of when it launches later this month, with a new report claiming production yields for the iPhone Duo remain relatively low.

Supply chain sources cited by Jiemian News claim Foxconn is currently achieving assembly yields of just over 60% for the iPhone Duo. Production volumes are also reportedly limited, as manufacturing lines continue to undergo adjustments ahead of the phone’s October 23 release.

The difficulties apparently extend across several parts of the manufacturing process. Foxconn is said to still be fine-tuning equipment, production methods and other settings, while some components supplied to the manufacturer have also faced problems.

Samsung Display’s foldable OLED panels have reportedly suffered from low yields, while delays affecting other components have reduced the amount of time Foxconn has had to optimise final assembly.

One particularly challenging part of the iPhone Duo is its hinge. The mechanism reportedly consists of more than 100 individual parts that need to fit and operate within extremely tight tolerances. Small differences between components can therefore have an impact on the completed device.

Apple reportedly explored using liquid metal for some of the hinge components before mass production but eventually opted for a different solution. Changing course now would be difficult, as Apple would need to produce and test new prototypes before working with suppliers to make further production adjustments.

Those challenges may not disappear quickly. One source claims it could take between six months and a year for manufacturing yields to reach the level Apple is aiming for.

There are ways Apple and its suppliers could potentially increase the number of finished phones. Apple could relax its quality requirements, for example, while suppliers could increase the pace of production. But pushing manufacturing lines harder could also increase the number of defective units being produced.

None of this necessarily means the iPhone Duo will be delayed. Apple unveiled the foldable at its “Surprise and Shine” event on September 12 and has announced that preorders will begin on October 16 before sales start on October 23.

The iPhone Duo starts at A$3,499 in Australia, making it one of Apple’s most expensive smartphones to date.

For now, those launch dates remain unchanged. But if Foxconn’s yields are still only slightly above 60% as production ramps up, Apple may have a limited number of iPhone Duo units available during the first weeks of release.