ya, guess I blamed the wrong party
iPad1: 127MB/256MB (crash amount/total amount)
I was testing on iPad2. It crashes at 148mb precisely. My game size is around 29mb. As it;s mini RTS, it generates way more sprites than what i expect. The initial memory needed is around 500mb. I got this info after testing it on Nexus 10. The only way to solve it is via lazying/additive loading. I know u3d pro has this feature. imho, using a 3D engine to make a 2D game is quite stupid. Anyway, let's wait for next patch.