Android game does not work when lightmap included (black screen instead)

Hello I have a weird problem. My game used to work perfectly on android device until i baked lights. With lightmaps included I can see only black screen without any response, sometimes my phone restarts after some time, sometimes i have to unplug battery to restart it. Any suggestions what could be wrong? I don't override texture compression, I have 6 lightmaps 1024px x 1024px. My android version is 2.3.3 (I know, it's old but I prefer to test my game on an old device), my phone is Samsung Galaxy S plus. Unity demo Angry Bots works perfectly on my device (with 3 lightmaps included).

Any ideas? How can I possibly debug this problem from device? Is there any log left by Unity on the device?

Thanks!