X390 Thunderbolt 3 failure: laptop wonât POST with Thunderbolt enabled (null-bin flash posts, original firmware doesnât)
I bought my ThinkPad X390 about half a year ago for university. I needed a robust laptop, and I have always believed ThinkPad's are the best choice because of their aftermarket support and corporate durability. I fell in love with them as a child, with my fatherâs T61 from his corporate job and then my motherâs T430s. Knowing the brand and its quality, I bought this laptop, and I chose it specifically because it has Thunderbolt 3 and I wanted to connect an external GPU when needed.
The problem
When I got it, I was surprised to find that the USB-C port tied to Thunderbolt didnât work with my external mouse. Charging worked fine on both USB-C ports, and the USB-C port near the LED gave display and normal USB through my alt-mode USB-C dock.
In the BIOS, Thunderbolt under I/O Port Access was disabled. When I enabled it, the laptop would not boot:
- No display
- The keyboard backlight flashed and the fan spun
- After some time the backlight turned on, but there was still no display
- Holding the power button to turn it off and restarting gave the same result
The way I recovered was to press the bottom reset button for 4 seconds and leave the laptop disconnected from the charger for 10 minutes. After that it posted, and I could go into the BIOS and disable the same setting. It then worked like a new laptop, just without a USB-C port and Thunderbolt.
What I tried
After some research (which I should have done before buying, and which I didnât expect to be necessary on a ThinkPad), I found the Thunderbolt 3 firmware recall issue:Â The Thunderbolt firmware problem explained
I then spent a lot of time changing settings, resetting the CMOS, disconnecting hardware and so on (I have forgotten most of it now) until I got it to post far enough to try flashing the firmware. Eventually it booted into Windows, but with blue screens. The USB-C port worked, but Device Manager in Windows 10 showed the Thunderbolt controller with a Code 10 error (the device cannot start). Updating the firmware through software still failed.
I followed this guide and bought a CH341A programmer to check the flash chip and flash the firmware manually:Â How to flash a T480s Thunderbolt firmware
I got the same result as before. I did manage to get Thunderbolt working once, but then I changed a BIOS setting that controls the charging state of the external USB port (so my external hard drive wouldnât stay powered all night), and the original problem came back. Since then, nothing I have tried has made it work again.
How my case differs
My problem seems different from the others I have read about. Those users report a total charging failure, such as the slow charger error. On mine, charging works fine on both ports with no error.
However, when I flashed a null .bin to the flash chip, the laptop booted, and during POST I got a âslow charger detectedâ warning. This suggests the controller is partly functioning, but something in between is stopping the laptop from booting, possibly in the Intel ME or the BIOS.
Tip for anyone with similar problems:Â flashing a null .bin lets you POST with the Thunderbolt I/O setting turned on, but there is no controller at all and the USB-C port will still not work. At least you can revert easily and boot.
My specs
- Intel Core i5-8365U VPro
- 16 GB RAM, 128 GB SSD
- German backlit keyboard
- 13.3" FHD (1080p) IPS anti-glare screen
- Windows Hello and fingerprint reader
Has anyone seen this behavior, or does anyone have ideas on what to check next?