Crash on Iphone4 but work on Iphone4S - PresentContextGLES()

Hi,

After playing 1-2min, my game crash only on Iphone 4 , ios7 and work perfectly on Iphone 4S, ios7 too.

DisplayManager.mm

[surface.context presentRenderbuffer:GL_RENDERBUFFER_OES]; Thread 1 : EXC_BAD_ACCESS

On patch note : 4.1.3, “Fixed crash when unloading unused assets.” , That is exactly what happen on my game. I use the last version of Unity 4.2.1. The problem is still present, Do you have any idea ?