It's hard to tell what's going on.
The original story (The Big Hack) sounds scary but doesn't name any sources and mentions motherboards and modifying the OS. It also includes this line about the trade war and tariffs. (This mentions network cards but the story itself claims modifications to motherboards)
The ramifications of the attack continue to play out. The Trump administration has made computer and networking hardware, including motherboards, a focus of its latest round of trade sanctions against China, and White House officials have made it clear they think companies will begin shifting their supply chains to other countries as a result.The "New Evidence" story, New Evidence of Hacked Supermicro Hardware Found in U.S. Telecom is not about a modification to a motherboard but of a "network connector" which wouldn't affect the OS.
Also, its source is an ex-Israeli Military intelligence office who can't really be specific due to a non-disclosure agreement. How convenient....
Appleboum previously worked in the technology unit of the Israeli Army Intelligence Corps and is now co-chief executive officer of Sepio Systems in Gaithersburg, Maryland. His firm specializes in hardware security and was hired to scan several large data centers belonging to the telecommunications company. Bloomberg is not identifying the company due to Appleboum’s nondisclosure agreement with the client. Unusual communications from a Supermicro server and a subsequent physical inspection revealed an implant built into the server’s Ethernet connector, a component that's used to attach network cables to the computer, Appleboum saidMeanwhile, all the vendors are basically claiming BS. The Cybersecurity World Is Debating WTF Is Going on With Bloomberg’s Chinese Microchip Stories
So at this point, I'm leaning toward a mostly BS story, planted as sort of an October Surprise using a national security scare to bump up Trump and R's ratings (see this post ), give credence to the trade war with China, and maybe take some computer and network hardware business from China.