Lenovo statement: Thunderbolt firmware responsible for ThinkPad USB C failures

We recently reported on failures of Thunderbolt controllers and investigated the topic further in a comprehensive way. Additionally, we sent some questions to Lenovo about the ThinkPad USB C failure - questions that were answered.

What we learned is that our suspicions about the cause of these ThinkPad Thunderbolt controller failures were pretty much on point: The failures do not stem from a defective controller chip design or overheating. They occur because one of the firmware updates released last years was flawed. This firmware version irreversibly damages the SPI-ROM of the Thunderbolt controller over time.

This also explains why the issue is a recent phenomenon: Affected older systems like the Lenovo ThinkPad T470 or T480 ran fine for years. The issues began when the flawed Intel firmware update was released last year. Meanwhile, the reason why some ThinkPads with Thunderbolt controllers like the X1 Extreme or ThinkPad P1 are not affected is that they use a different firmware and never were exposed to the flawed version.

Lenovo gave us this statement regarding the issue:

Lenovo identified and provided a fix for this issue in August 2019, since when the patch has been pushed through Lenovo Vantage to affected users. While we believe that the impact of this will be minimal, should customers experience difficulties, they should contact Lenovo Technical Support who will be glad to help.

There is one additional question we had: What happens with customers who have this issue with out of warranty machines? Unfortunately, Lenovo did not give us an answer about this question yet.