While the 4.7-inch iPhone 6s on some U.S. carriers is still available for delivery on the September 25th launch date, nearly all of the larger, 5.5-inch iPhone 6s Plus models are now scheduled to deliver in 3-4 weeks for new orders. According to KGI Securities, this is not entirely due to high demand for the largest iPhone model. According to a new note from the firm, the constraints are actually due to supply problems with the 6s Plus’s backlight hardware:

Nonetheless, KGI says that it expects Apple to have between 1.5 and 2.5 million 6s Plus units ready to go for the September 25th ship date. Earlier this morning, Apple said that new iPhone pre-orders are currently outpacing the success of last year’s iPhone 6 and iPhone 6 Plus pre-order period. This, of course, is not entirely surprising as this year’s rollout includes China, while last year’s China launch happened a bit later than the first wave.