Here's a picture of the hidden storage area under the trunk felt pad behind the battery compartment.
Forum fellow Derek8819 pointed out that, on former 1ers, this space was used for installation of add-on modules (such as SATNAV and Bluetooth). In the 1M these devices, if chosen as option, are installed in the head unit.
It is suspected that this empty cavity could be related to the 1M drone:
http://www.1addicts.com/forums/showt...php?p=12850245
