Smartphone maker BlackBerry announced Monday the sale of most of its Canadian properties to San Francisco-based real estate investment firm Spear Street, for Can$305 million (US$278 million). The deal includes more than three million square feet of office space as well as vacant lands. BlackBerry said in a statement it will lease back a portion of the space. The real estate selloff is part of BlackBerry's turnaround plan, refocusing on its core software and services business after a dismal few years. BlackBerry helped create a culture of mobile users glued to smartphones, but lost its luster as many moved to iPhones or devices using Google's Android software. After posting record losses last year, the company brought in new management and outsourced its handset production to Taiwan-based Foxconn.