TI OAD on android is too slow, is it normal?

When i do the TI OAD function both in my ios app and android app, the ios only take 2minutes to finish the update, but the android takes up to 10 minutes. Does any one have the same problems? As i found, the ios demo will send the block image initiative by using NSTimer and the block size is 16 byte, the rate is 0.05s. It is successfully to use this way. However, when i try to use the save way in android code, it doesn't work. In android, when i send a block image to bluetooth, i must wait the notify, then i can send a new block again. It takes too long to finish the update. I use the TI 2541.