I created a full white texture with 4x4 size. Unity requires that compressed texture size should be at least 4x4. This will cause some artifact on some Android device, and the frame rate was very slow.
Later I tried to make true color for this small texture. This time no artifact and no frame rate slow problem.
I think the texture compression is hardware bind. Althought Unity provide some compression methods, not all of them could be supported well by various of devices.
Different devices may have different requirement even for the same compression. The most safe way is use true color for them.
Crash for small compressed texture on some Android device
原文：http://www.cnblogs.com/open-coder/p/4245562.html