By Karen Thomas, MSc, CFA at The Motley Fool Canada As a TSX stock that once soared above $250, Blackberry Ltd. (TSX:BB) has been through it all. The rise, the fall, and the in-between stagnant period of going nowhere. But through it all, there’s one thing that Blackberry has always maintained – technological excellence. Today, Blackberry is a TSX stock that’s gaining traction and momentum in both its business and its stock price. Here’s why this undervalued TSX stock is a great long-term buy. Blackberry: What happened to this TSX stock? First, a brief look at Blackberry’s history. Blackberry was once the undeniable leader in handheld phones. As you know, this is no longer the case, as Smartphones such as the iPhone and Android began to dominate the market in the early 2010’s. By 2016, the “Blackberry” phone was pretty much history. At that time, the company had to do something drastic to survive. It was a touch and go situation until finally, Blackberry opted to change course and embark on a transformation. Its areas of choice were the Internet of Thing (IoT) and cybersecurity industries. Both drew on Blackberry’s expertise and as this undervalued TSX stock strengthened its presence and focus on these areas, this expertise grew. The company’s reputation now proceeds it. As one would expect in such a situation, Blackberry’s stock price fell hard. In fact, it traded below $10 and stayed in this range for many years. The stock is currently trading at approximately $12.40. This is 46% lower than 2022 levels and way below its historic highs. Blackberry and the connected car For years, this undervalued TSX stock has been quietly working to establish itself as the leader in software technology for critical systems in cars, medicine, robotics, and other industrial uses. Recently, its QNX