From my understanding, most companies take the reference design from Arm and then alter it to fit their needs.
That’s a big part of what’s going on. ARM is trying to move into Qualcomm’s traditional business while Qualcomm is trying to move in ARM’s traditional business.
"Under Chief Executive Officer Rene Haas, Arm has shifted to offering more complete designs — ones that companies can take directly to contract manufacturers. Haas believes that his company, still majority owned by Japan’s SoftBank Group Corp., should be rewarded more for the engineering work it does. That shift encroaches on the business of Arm’s traditional customers, like Qualcomm, who use Arm’s technology in their own final chip designs.
Meanwhile, under CEO Cristiano Amon, Qualcomm is moving away from using Arm designs and is prioritizing its own work, something that potentially makes it a less lucrative customer for Arm. He’s also expanding into new areas, most notably computing, where Arm is making its own push. But the two companies’ technologies remain intertwined, and Qualcomm isn’t yet in a position to make a clean break from Arm."