Comment by fullofstack

from http://www.reddit.com/r/netsec/comments/209h4d/samsung_galax... : This is not a backdoor. It's a feature, and a reasonably common one for Qualcomm based devices. It's an interface to allow the modem access to a persistent data store (ie. eMMC modem partitions) even though only the application processor may access the MMC controller. Have a look at the rmt_storage client documentation found in a Qualcomm kernel tree. It used to be pretty common to ship a rmt_storage daemon to do the very same thing Samsung is being accused of here (hint: Nexus 5 still uses it), I don't know about other recent devices, but I'd imagine they'd employ something similar. Also, there are many more ways for the baseband to compromise the application processor, without an explicit interface.