Updated

If you're thinking of picking up a shiny new iPhone 6 on launch day, you may have to reset your expectations. According to a new report, Apple's suppliers are having trouble producing enough screens for at least one of the two expected devices, which could seriously limit availability.

Based on what two supply chain sources told Reuters, Apple wanted to initially use only one layer of backlight film on the 4.7-inch iPhone 6 in order to make it as thin as possible. But when the panel wan't bright enough the company reversed course. The resulting delay could mean less devices on store shelves, at least during the first weeks after launch.

MORE: iPhone 6 Rumors - Specs, Sizes, Camera, and More

The good news for shoppers is that output is reportedly back on track and "suppliers are working flat-out to make up for lost time." Those partners include Japan Display, Sharp and LG Display.mApple is also reportedly debuting a larger 5.5-inch version of the iPhone 6, which was expected to go into mass production after the 4.7-inch model.

Although there's no firm on-sale date for the iPhone 6 yet, Apple is expected to launch it at a Sept. 9 event in San Francisco. Based on various rumors, the iPhone 6 should pack a faster A8 processor, a more advanced camera--perhaps with a protruding or replaceable lens--and NFC capability for mobile payments. Plus, the sapphire crystal screen should be super tough.

The iPhone 6 will debut one week after Samsung's fall Unpacked event, where the company is expected to launch the Galaxy Note 4, the Gear Solo (a smartwatch that can make calls) and a virtual reality headset co-created with Oculus VR.