I used to write software for the cellular radio baseband. I certainly didn't put any backdoors in, but of course it would be possible. I don't think there is an

I used to write software for the cellular radio baseband. I certainly didn't put any backdoors in, but of course it would be possible. I don't think there is any conspiracy though, shared memory is just efficient and convenient for shuffling lots of data. Phone designers are not really trying to have security barriers between hardware components, and on many phones the baseband is inside the same chip as the main processor.