Apple is expected to announce a new iPhone in little over two weeks, but a last minute snag with the display’s backlighting may result in limited availability at launch. According to Reuters, the company put screen assembly on hold for part of June and July because the original design was not bright enough.

The problem cropped up as Apple wanted to reduce the material used for the backlight from the standard two layers to just one, in hopes of thinning the phone. But without that second layer the company found that the device’s display wasn’t bright enough to meet its standards.

Although the setback doesn’t appear to have delayed Apple’s launch plans, it’s unclear if this pause in manufacturing will have an impact on the initial shipments of the new iPhones. Reuters’ sources claim output is now back on track and suppliers are working flat-out to make up for lost time.

Companies making the screens include Japan Display, LG Display and Sharp. The former is said to be the lead supplier for the new iPhone panel and as much as a third of the firm’s total revenue for the year is coming from Apple.

Although we won’t know for certain until September 9, the next iPhone is expected feature a slightly redesigned body, with a 4.7-inch model arriving initially and possibly followed a 5.5-inch variant sometime later. Along with the larger screen, the iPhone 6 may include a more durable sapphire display, and the usual range of performance and camera improvements.