According to Macotakara, the problem was in paint application, resulting in discoloration and general malaise.
According to a source, specified printing white color for iPhone 4 brings poor yield and then huge number of defective products. This is the reason of disturbing to start manufacturing, a source said.
To solve this problem, a Japanese company developed miracle painting material which is able to be set thickness of painting layer.
Hopefully this means the rise of the White, snowy iPhone to match this white, snowy January.